CoEPP ANNUAL REPORT 2015

ARC Centre of Excellence for Particle Physics at the Terascale

ANNUAL REPORT 2015 ANNUAL www.coepp.org.au REPORT 16 Centre nodes

Monash node Adelaide node School of Physics and Astronomy 1st floor, Physics Building Clayton Campus North Terrace Campus Monash University VIC 3800 The University of Adelaide SA 5005 T +61 3 9902 4981 T +61 8 8313 3533 E [email protected] E [email protected]

Sydney node Melbourne node School of Physics, Building A28 David Caro Building (Bld 192) Camperdown Campus Parkville Campus The University of Sydney NSW 2006 The University of Melbourne VIC 3010 T +61 2 9351 2482 T +61 3 8344 5428 E [email protected] E [email protected]

Partner institutions

CONTENTS

3 ACRONYMS AND ABBREVIATIONS 44 OUTREACH AND ENGAGEMENT

4 ABOUT 48 PUBLICATIONS 5 About CoEPP 49 Refereed journal articles 6 Director’s report 51 ATLAS collaboration 7 Chair’s report 55 Belle collaboration 8 International Advisory Committee’s report 56 CDF collaboration 9 Structure and governance 57 Refereed conference proceedings 11 Personnel 58 Conference presentations 61 CoEPP annual workshop 18 RESEARCH 19 Overview 64 PERFORMANCE 20 Higgs experimental program 65 Prizes and awards 23 Higgs theory program 66 Media report 25 Neutrino theory program 67 Centre-recognised leadership 26 Precision tests of the Standard Model 70 Key performance indicators 28 Dark matter 72 Financial statements 31 Searching for supersymmetry 74 Financial summary 34 Research computing 78 LOOKING AHEAD 35 Running and upgrading the experiment 36 Collaborations 79 Activity plan 82 Case study: Searching for new physics with 38 CONFERENCES AND WORKSHOPS computer vision 39 2016 CoEPP annual workshop and summer school in Torquay 40 SUSY 2016 41 INPC 2016 43 CosPA 2016

1 ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

2 ANNUAL REPORT ACRONYMS AND ABBREVIATIONS

AIDA An Inclusive Dilepton Analysis ATLAS A Toroidal LHC ApparatuS CERN European Council for Nuclear Research CMS Compact Muon Solenoid CoEPP ARC Centre of Excellence for Particle Physics at the Terascale CP charge parity DM dark matter fb femtobarn GAMBIT Global And Modular Beyond the Standard Model Inference Tool GeV giga-electron volt ICHEP International Conference on High Energy Physics IUPAP International Union of Pure and Applied Physics KEK High Energy Accelerator Research Organisation LHC Large Hadron Collider MSSM minimal supersymmetric Standard Model NMSSM next-to-minimal supersymmetric Standard Model QCD quantum chromodynamics SM Standard Model of particle physics SUSY supersymmetry TeV tera-electron volt WIMP weakly interacting massive particle WLCG Worldwide LHC Computing Grid

3 ABOUT

The ARC Centre of Excellence for Particle Physics at the Terascale (CoEPP) is a collaborative research venture between the universities of Melbourne, Adelaide, Sydney and Monash. ANNUAL REPORT

About CoEPP

The Australian Research Council (ARC) Centre of Excellence for Particle Physics at the Terascale (CoEPP) is a collaborative research venture between the universities of Melbourne, Adelaide, Sydney and Monash.

CoEPP fosters links between experimental and theoretical particle physics, links Australian research to significant international research Mission centres, establishes strong Australian grid and cloud computing • To enable young Australian scientists direct access to this most expertise, and further develops accelerator technologies in Australia. exciting field of endeavour on a footing where they will be competitive with their international peers. Vision • To inspire a new generation of young Australians to pursue careers in science and technology. The Centre will exploit a once-in-a-generation opportunity for • To lead Australia in the field of high-energy physics research, fundamental scientific research in Australia through its involvement and to establish national awareness, pride and longevity in this with the Large Hadron Collider (LHC) at CERN. This includes field through international collaboration, excellence in research discovering new physical laws, recreating and investigating matter training and opportunity for engagement. under conditions that have not existed since the big bang, and producing and studying dark matter in the laboratory. The Centre will lead the nation in pursuing knowledge of the fundamental laws of particle physics through a deepening engagement in the international field of high-energy particle physics.

5 ABOUT ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

Director’s report

2016 marks CoEPP’s sixth year of operation and has been our most productive year to date. We began the year with our biggest ever CoEPP scientific workshop in Torquay, Victoria. More than 150 representatives from Australia and overseas participated. We have expanded the national particle physics program and have an unprecedented number of research students. CoEPP organised major international conferences in Adelaide, Melbourne and Sydney, and cemented collaborative exchange relationships with Fermilab in the United States and the Institute of High Energy Physics (IHEP) in China.

The LHC operated beautifully at 13 TeV energy and has delivered Fermilab, the United States major high-energy physics laboratory, a lot more data than was anticipated. More than 40 petabytes and CoEPP recently signed an international Cooperative Research of data have streamed through the Worldwide LHC Computing and Development Agreement, which is a significant step in forging Grid since the LHC restart, and our researchers have been busy active partnerships to tackle shared challenges in physics research. analysing these data. The focus now is on precision measurements The agreement will initially facilitate exchanges in both directions of the Higgs boson, as well as looking at new ways of searching for of researchers, technical staff and students to work on a range supersymmetry (SUSY) and the potential for dark matter production. of activities, including advanced theoretical physics, precision CoEPP researchers have a strong reputation in various Higgs decay measurement techniques, advanced research computation methods, analyses, including the Higgs decaying to a pair of tau leptons, the underground experimentation and accelerator R&D. We also signed Higgs to WW channel, Higgs production in association with top a collaboration agreement with IHEP. Progress continues with the quark pairs in leptonic final states as well as Higgs decaying into a SuperKEKB project at KEK in Japan. Both positron and electron pair of photons, and rare and exotic Higgs searches. beams were first circulated in February. CoEPP experimentalists are active in pursuing the future program of the Belle II experiment at Our theorists have made important contributions to Higgs studies the unique and important SuperKEKB. The next round of tests is with development of strategies to measure Higgs boson couplings, scheduled for mid-2018, with the commencement of the program model building, and looking at cosmological and astrophysical with a completed detector due from early 2019. manifestations of Higgs physics. Theorists continue their research on dark matter with important contributions to the collider With all the very positive results from our current program and the search through the mono-X program, as well as indirect detection acclaim received, it was with great disappointment we learned of techniques, and model building. A key legacy of CoEPP has been the failure in our bid to win funding in the 2017 round of ARC Centre theorist–experimentalist connection, which marks us as innovators in funding. With the unanimous judgement of CoEPP’s success as an the international context. ARC Centre and the recognised quality of our work, this result is hard to understand. However, we will continue as a Centre beyond 2017 The highly successful pre-SUSY Workshop and SUSY 2016 and are actively following the many constructive ideas proposed to Conference took place in Melbourne in early July. Thanks to a team seek avenues for additional funding to continue CoEPP operations effort between CoEPP Monash and Melbourne, the conference had beyond the current ARC funding period. Your ongoing commitment more than 270 participants, 220 abstracts submissions, 31 plenary and support are much appreciated. They will empower us to talks and an intriguing public lecture by Professor John Ellis on dark develop these ideas into concrete strategies and plans to maintain matter and SUSY. Talks explored the unknown, and probed some and expand particle physics research in Australia. I look forward to new ideas in theoretical and phenomenological aspects of SUSY. further developments and will keep you informed as they evolve. Experimental results and future capabilities tempered the theorists’ extravagance with a dash of reality! In September, the Adelaide node hosted the International Conference on Nuclear Physics 2016, together with the Australian National University and the Australian Nuclear Science and Technology Organisation. The large-scale conference attracted international delegates from many laboratories including TRIUMF, JLab, IUPAP and RIKEN. A diverse range of talks reviewed and discussed recent progress and development in nuclear physics Professor Geoffrey Taylor research, including the discovery of element 113 at RIKEN. Centre Director CoEPP Sydney ran the 13th International Symposium on Cosmology and Particle Astrophysics. Latest results and ideas in the areas of particle physics, cosmology and astrophysics were presented over five days in December.

6 ABOUT ANNUAL REPORT

Chair’s report

During its 5-year run, the Advisory Board has become really impressed with the number of scientific interfaces that CoEPP manages for the physics community. Best known are the interfaces with CERN and the LHC. These provide scientific opportunities for dozens of Australia’s highly talented and motivated graduate students and early career researchers. CoEPP also interfaces with ANSTO, Australia’s only government laboratory in nuclear physics. In October, I was interested to talk to the then Minister for Industry, Innovation and Science, the Hon. Greg Hunt. He boasted to our small delegation that he ran Australia’s only accelerator, the Australian Synchrotron. Indeed, he does, through ANSTO, which may be better known for running Australian’s only nuclear reactor.

CoEPP also interfaces with several international university leaders Given all CoEPP’s opportunities and interfaces, an Australian Centre in high-energy physics and national labs, such as the United States of Excellence in particle physics is greatly needed, and we expect to Department of Energy’s Fermilab, also visited by the Minister in apply to the ARC at the next opportunity. But there may be some October. CoEPP is our link to new accelerators in Asia and to the real opportunities earlier than that. The Advisory Board is exploring Nobel Prize–winning Japanese research effort in neutrino physics. these options.

CoEPP is home to Australia’s astroparticle research. Some of the most interesting questions in physics, such as the nature of dark matter and the dominance of the Professor Jeremy Mould universe over the antiparticle universe, will Chair, Advisory Board likely be answered in the coming decades, and Australia’s contribution to answering these and other questions will come from CoEPP or its successor.

It is time to rethink what CoEPP’s successor will be, and our Advisory Board is now engaged with that question. Some will consider it surprising that CoEPP will not immediately be renewed by the ARC when funding is fully expended in 2018. However, physics is in such an exciting phase now that it is hard to criticise the ARC for investing in such irresistible opportunities as the Future Low-Energy Electronics Technologies (FLEET) centre, rather than renewing CoEPP. FLEET points out to all of us that the power used by our smart phones is not just battery power; it’s the gigawatts used by servers at remote companies providing instant answers to these communicators. When that’s added in, we’re told, our smart phone uses as much power as our fridge. Australia wants to contribute to finding the replacement for the humble transistor, too. There is an embarrassment of opportunities in physics and insufficient research funds to take up all these challenges.

7 ABOUT ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

International Advisory Committee’s report

The International Advisory Committee (IAC) is made up of leading particle physics researchers; it meets once a year to discuss and guide the scientific direction of the Centre.

The 2016 meeting of the IAC and Partner Investigators was held on Australian participation – through CoEPP – in the ITK Upgrade has 11 August, at the University of Chicago, immediately following the many advantages. International Conference on High Energy Physics (ICHEP). Of note from the IAC was the very impressive increase in student Present were IAC Chair Rolf Dieter-Heuer, and members Peter numbers throughout CoEPP’s operation. They asked about the Jenni, Young-Kee Kim (new to the IAC) in person and John Ellis gender balance among our students, which compares very well by teleconference. Also present were Partner Investigators, Karl among physical sciences research groups; CoEPP will continue to Jacob and Allan Clark in person, and Andy Parker, Mark Kruse and work to improve the gender ratio. The IAC also noted that the large Chiara Meroni by teleconference. CoEPP members Geoffrey Taylor number of international research students seeking a place with (Director), Tony Williams, Paul Jackson, Peter Skands and Tony CoEPP was clear recognition of our esteem worldwide. Limosani were also present. The IAC noted the large number of major conferences being held by The main item of business was the status of the proposal to the CoEPP and its members and encouraged the idea of holding pre- ARC for a second 7-year funding round for Australian high-energy and post-conference workshops to offset the large distance travelled physics. Although we now know that the proposal was unsuccessful, by colleagues in the northern hemisphere. it was satisfying to see the IAC’s confidence in our ability to build CoEPP was encouraged to continue its successful outreach upon the strengths already in place and our capability of carrying program, with the suggestion that events in cities and large out the very significant plans clearly stated in the proposal. centres in Australia without a CoEPP node be pursued to broaden In parallel with the Centre renewal proposal, a description of the national exposure. upcoming ARC Linkage Infrastructure, Equipment and Facilities CoEPP also congratulated Partner Investigator Professor Karl Jacob (LIEF) funding round was provided. The IAC encouraged us in plans for being elected spokesperson of the ATLAS collaboration from to participate in the major ATLAS Phase II Upgrade in which, in January 2017. Karl follows in the footsteps of very significant ATLAS particular, the existing Inner Detector will be completely replaced leaders Peter Jenni (also an IAC member), Fabiola Gianotti and by an all-silicon inner-tracking detector, “ITK”. With our expertise in David Charlton. silicon detector development and construction, in advanced track trigger electronics and programming, and in data acquisition, the

IAC member Professor Karl Jakobs, ATLAS collaboration spokesperson from 2017

8 ABOUT ANNUAL REPORT

Structure and governance

The operation of the Centre is managed through committees and management teams. The organisational structure is designed to support a focused, coordinated program and to sustain the ability to deliver change over an extended period.

Operation and management Advisory Board Chaired by Professor Jeremy Mould, the Advisory Board meets every The Centre management structure comprises the Director, Professor 6 months to provide advice to the Centre Director; and to provide Geoffrey Taylor; the Associate Director, Professor Anthony Thomas; oversight, review and comment on matters of strategic direction, the and the four node directors who manage local node issues. These conduct of research and other relevant Centre activities. The board staff comprise the Centre Executive Committee, which meets met at the CoEPP Annual Scientific Workshop in Torquay in February monthly throughout the year in four face-to-face meetings – one and at the University of Melbourne in September. Members of the at each node – and at other times by teleconference, to ensure as board are: wide participation as possible, given the varied travel schedules of the members. • Professor Jeremy Mould (Chair), Professor of Astrophysics, Swinburne University A Centre Manager supports the Director and the executive team, and oversees administrative, IT, outreach and communications support • Mrs Sarah Brooker, Managing Director, Science in Public for the Centre. The Centre Manager also works with node directors • Professor Mike Brooks, Deputy Vice-Chancellor (Research) to ensure the proper flow of accounting information between the University of Adelaide Centre and the nodes. Financial statements are generated quarterly • Professor Karen Day, Dean of Science, University of Melbourne and financial reports are presented annually to the board, with (Deputy Vice-Chancellor (Research) nominee) interim statements at the half-yearly meetings. Two other key • Professor Bruce McKellar AC, President, International Union of roles in the Centre comprise Outreach and Communications, and Pure and Applied Physics, and Honorary Professorial Fellow, Research Computing. Outreach activities include national and local University of Melbourne programs for school students, as well as public outreach programs; communications activities include public-facing elements such as • Professor Michael Morgan, Head, School of Physics, Monash media liaison, promotion of the Centre, its research and researchers, University (Deputy Vice-Chancellor (Research) nominee) and management of web and social media. The Centre Research • Dr Adi Paterson, Chief Executive Officer, Australian Nuclear Computing facility enables the Centre to maintain its pledge to Science and Technology Organisation the Worldwide LHC Computing Grid by providing Tier 2 computer • Professor Michael Thompson, Professor in Zoology, University of facilities to the ATLAS experiment and local analysis support for the Sydney (Deputy Vice-Chancellor (Research) nominee). Centre’s experimental researchers and students.

Centre Advisory Committees

International Advisory Committee The IAC meets annually and provides independent scientific expertise, advice and experience from established research centres and leading international laboratories. Members of the IAC met in August during ICHEP 2016 in Chicago, and were briefed on recent Centre activities. Members of the IAC are: • Professor Rolf-Dieter Heuer (Chair), President of Deutsche Physikalische Gesellschaft (German Physical Society) • Professor Hiroaki Aihara, Vice President, University of Tokyo, and Associate Director, Institute for the Physics and Mathematics of the Universe, Japan • Professor John Ellis, CERN, and Clerk Maxwell Professor of Theoretical Physics at King’s College London, United Kingdom • Professor Peter Jenni, CERN, and Guest Scientist with the Albert-Ludwigs-Universität, Freiburg, Germany • Professor Young-Kee Kim, Louis Block Professor of Physics, University of Chicago, United States (from July 2015).

9 ABOUT ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

Meeting schedules

Meeting Attendees Frequency Timing/venue International Advisory IAC and Director Annually Held during ICHEP in August Committee Advisory Board Advisory Board and Director 6-monthly Held at the Torquay workshop in Centre academics were also invited February and at the University to the Torquay workshop meeting of Melbourne in September Centre Executive Director, Executive Committee, Monthly Four face-to-face meetings per Centre Chief Investigators and year; remaining meetings by academics teleconference CoEPP Experimental Particle Experimental particle physics staff Weekly Teleconference between the Physics Group and students from Melbourne, three experimental nodes of Adelaide and Sydney universities the Centre Internal Annual Research All CoEPP research and Annually Held in Torquay in February Workshop administration staff and students, and representatives from Partner Institutions, IAC and Advisory Board Theory Group Journal Club Theory researchers and students Weekly Held by teleconference between from all nodes all nodes

CoEPP governance structure

International Advisory Director Advisory Board Committee Professor Geoffrey Taylor

Associate Director Centre Manager Professor Anthony Thomas David Varvel

Senior Communications and Research Computing Manager Outreach Consultant Lucien Boland Caroline Hamilton

Melbourne Node Director Adelaide Node Monash Node Director Sydney Node Director Professor Director Associate Professor Professor Raymond Volkas Professor Anthony Thomas Csaba Balázs Kevin Varvell

10 ABOUT ANNUAL REPORT

Personnel

Chief investigators

Professor Geoff Taylor Associate Professor Professor Anthony Thomas Professor Kevin Varvell Csaba Balázs Centre Director Node Director Node Director University of Melbourne Node Director University of Adelaide University of Sydney Monash University

Professor Ray Volkas Professor Elisabetta Barberio Associate Professor Nicole Bell Dr Antonio Limosani Node Director University of Melbourne University of Melbourne University of Sydney University of Melbourne

Associate Professor Professor Anthony Williams Dr Bruce Yabsley Associate Professor Martin Sevior Ross Young University of Adelaide University of Sydney University of Melbourne University of Adelaide

11 ABOUT ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

Additional academic staff

Dr Matthew Dolan Dr Robert Foot Associate Professor Dr Archil Kobakhidze Paul Jackson University of Melbourne Senior Researcher, ARC Future Fellow, University of Melbourne ARC Future Fellow, University of Sydney University of Adelaide

Dr Michael Schmidt Associate Professor Dr Phillip Urquijo Prof German Valencia Peter Skands University of Sydney ARC Future Fellow, Monash University ARC Future Fellow, University of Melbourne Monash University

Dr Martin White ARC Future Fellow, University of Adelaide

12 ABOUT ANNUAL REPORT

Honorary fellows and associates

Professor Allan Clark Dr Shivani Gupta Dr Girish Joshi Dr Katherine Mack University of Geneva, Visiting Research Associate, Honorary Principal Fellow, Honorary Fellow, Switzerland University of Adelaide University of Melbourne University of Melbourne

Professor Bruce McKellar AC Associate Professor Dr Brian Petersen Dr Aldo Saavedra Lawrence Peak Honorary Professorial Fellow, Honorary Fellow, Honorary Fellow, University of Melbourne Honorary Fellow, University of Melbourne University of Sydney University of Sydney Partner investigators

Professor Tony Gherghetta Professor Karl Jacobs Professor Mark Kruse Professor Chiara Meroni University of Minnesota, University of Freiburg, Germany Duke University, United States Istituto Nazionale di Fisica United States Nucleare, Italy

Professor Andy Parker Professor Mark Trodden University of Cambridge, University of Pennsylvania, United Kingdom United States

13 ABOUT ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

Postdoctoral researchers

University Name Monash University Sujeet Akula Peter Athron Andrew Fowlie Haitao Li Tong Li

University of Adelaide Juan Herrero Garcia Lawrence Lee Marek Lewicki Jinmian Li Hrayr Matevosyan Roman Nevzorov Andreas Petridis Pankaj Sharma

University of Melbourne James Barnard Giorgio Busoni Yi Cai Tyler Corbett Noel Dawe David Dossett Takashi Kubota Chunhua Li Federico Scutti Francesco Tenchini Francesca Ungaro Zhao-Huan Yu Daniele Zanzi

University of Sydney Kevin Finelli Kristian McDonald

Anthony Morely Participants at CoEPP's annual scientific workshop Jin Wang Lei Wu

14 ABOUT ANNUAL REPORT

Students

University Study Name University Study Name Monash Honours Andrew Lifson University Masters Wesam Badr University of Melbourne Shi Qiu Innes Bigaran

PhD Cody Duncan Byung Cheon Nadine Fischer Patrick Dawson

Giancarlo Pozzo Shanette de la Motte Graham White Joshua Ellis

University Honours Paul Alvino Benjamin Graham of Adelaide Joshua Crilly Stephen Keyte Jake Guscott John Koo Patrick Riley Ibtihal Mahmood

Masters Luciano Carneiro-Guedes Peter McNamara Guy Pitman Roberto Munoz Harry Poulter Nina Rajcic Stephen Tronchin Tristan Ruggeri

PhD Ankit Beniwal Martine Schroor Damir Duvnjak Kim Smith Dylan Harries Christian Sotomayor Sophie Hollitt Aghuistin Steele Nicolas Ivancevic Justin Tan Kay Marie Martinez Scott Williams

Zachary Matthews Table continued over page Daniel Murnane Jason Oliver Robert Perry Anum Qureshi Filip Rajec Marco Santoni Andre Scaffidi Abhishek Sharma Sophie Underwood

15 ABOUT ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

University Study Name University Study Name University of PhD Tristan Bloomfield University of Honours Ruihao Li Melbourne Sydney (continued) Amelia Brennan Masters Nadia Toutounji Giacomo Caria Lachlan Vaughan-Taylor

Jackson Clarke PhD Somasuntharam Arunasalam Peter Cox Neil Barrie Tomasz Dutka Curtis Black Alexander Ermakov Rupert Coy Leon Friedrich Bahman Ghadirian Johnathan Gargalionis Cyril Lagger Anton Hawthorne-Gonzalvez Shelley Liang Chia-Ling Hsu Adrian Manning Anders Huitfeldt Mark Scarcella David Jennens Alex Spencer-Smith Brian Le Carl Suster Rebecca Leane Matthew Talia Stephen Lonsdale Jason Yue Caitlin MacQueen Lara Mason Millie McDonald Marco Milesi Francesco Nuti Luis Pesantez Joni Pham Pere Rados Isaac William Sanderson Laurence Spiller Thor Taylor Timothy Trott Eiasha Waheed David Wakeham James Webb

16 ABOUT ANNUAL REPORT

Professional staff

Name Position Node Mr Tiziano Baroncelli Engineer, Belle II University of Melbourne Mr Tommaso Baroncelli Engineer, Belle II University of Melbourne Mr Lucien Boland Research computing manager University of Melbourne Dr Goncalo Borges Research computing officer University of Sydney Dr Catherine Buchanan Monash node administrator Monash University Mr Alessandro Caronti Project administration officer University of Melbourne Mr Sean Crosby Research computing administrator and University of Melbourne developer Mr Stephen Gregory Engineer University of Melbourne Ms Caroline Hamilton Senior communications and outreach University of Melbourne consultant Ms Ying Hu Melbourne node administrator University of Melbourne Ms Winnie Huang Centre administrator and PA to Director University of Melbourne Ms Sharon Johnson Adelaide node administrator University of Adelaide Dr Diana Londish Sydney node administrator University of Sydney Dr Padric McGee IT support University of Adelaide Ms Mary Odlum Finance Officer University of Adelaide and University of Melbourne Ms Silvana Santucci Adelaide node administrator University of Adelaide Ms Tracy Sproull Finance Officer University of Melbourne Mr David Varvel Centre manager University of Melbourne

17 ABOUT RESEARCH

CoEPP is the foremost particle physics research centre in Australia. Centre members undertake groundbreaking and transformational particle physics research, and work on the most pressing questions in the field, including tests of the Standard Model of particle physics (SM), Higgs boson properties and Higgs decay analysis, new physics beyond the SM, supersymmetry (SUSY) and dark matter (DM). A major focus of research within CoEPP is the ATLAS experiment at CERN.

RESEARCH ANNUAL REPORT

Overview

CoEPP’s work at ATLAS includes the analysis of Higgs boson decay strong. Theoretical and experimental researchers across the nodes modes (which is vital for characterising the Higgs boson), and the meet weekly via teleconference. CoEPP researchers also work with development of new and refined theoretical models and analysis individuals across the globe on specific projects and, besides ATLAS, techniques. Centre work studies physics beyond the SM, the are members of many other particle physics collaborations, including search for the origins of neutrino mass, fine-tuning constraints in Belle II and GAMBIT. supersymmetric models and the elusive search for DM. Theoretical work underpins the experimental studies, with theorists and experimentalists working collaboratively on the many areas of study in the Centre’s rich research program. Cross-node collaboration is

XXXX

19 RESEARCH ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

Higgs experimental program

Researchers Introduction about 125 GeV, which is compatible with the mass measured more accurately in separate analyses of Elisabetta Barberio The discovery of the Higgs boson was the most events where the Higgs boson decayed into pairs significant achievement of the ATLAS and CMS of vector bosons. One of the main challenges in the Noel Dawe experiments in the first period of data taking H → ττ analysis is to efficiently reconstruct and Paul Jackson (Run 1) from the LHC, and proved that the SM is a identify the hadronic decays of the tau leptons. self-consistent theory. After a 2-year shutdown for These tau lepton decays occur with the highest Takashi Kubota essential upgrades, the LHC began its Run 2 phase in probability, but the resulting hadrons are difficult Lawrence Lee 2015, with collisions set at the unprecedented energy to distinguish from jets of hadrons produced by of 13 TeV. In 2015 and 2016, the LHC delivered more fragmenting quarks and gluons emitted from the Tony Limosani than 40 fb-1 of proton–proton collision data – more proton–proton collisions. CoEPP researchers have Anthony Morley than projected. With even more data expected in a longstanding and significant contribution in both 2017, the Higgs research program is in full swing once the search for H → ττ and the reconstruction Geoffrey Taylor again. Now that the discovery of the Higgs boson has and identification of the hadronically decaying tau Kevin Varvell been well established, Higgs searches have turned leptons. into precision measurements. The aim is to measure Jin Wang CoEPP researchers are also leading the search for – as precisely as possible – all the properties of these decays by targeting one specific production Martin White the new particle and compare them with the SM mode: Higgs boson production in association with predictions. Deviations may give hints of extensions Daniele Zanzi a vector boson (VH). This production mode is of the SM with other Higgs boson partners, or of new subleading with respect to those exploited in the physics at higher energy scales. main H → ττ search, but observing this rare process Students CoEPP researchers have been actively studying the is relevant for determining Higgs boson properties 13 TeV data of Run 2. Parts of the ATLAS detector and testing SM predictions. Analysis of the data Curtis Black –1 and of the data acquisition and event reconstruction (20 fb ) collected at 8 TeV centre-of-mass energy David Jennens software have been upgraded, and properties of was published in Physical Review D (Phys. Rev. D 93, the proton collisions have changed with respect 092005). An upper exclusion limit on the production Brian Le to Run 1. That meant that the ATLAS detector and cross-section times branching ratio for VH (→ττ) Marco Milesi software had to be thoroughly commissioned with events is set at 5.6 times the SM prediction, and the the new data. CoEPP researchers contributed to the signal cross-section is measured to be 2.3 ± 1.6 times Francesco Nuti recommissioning and are now involved in the wide the SM prediction. Dr Geng-Yuan Jeng, a former Jason Oliver range of Higgs analyses outlined below. CoEPP researcher, coordinated the analysis. Jeng, Daniele Zanzi and PhD students Curtis Black and Pere Rados David Jennens established a data-driven method Laurence Spiller Research for estimating background events with misidentified muons and electrons and hadronically decaying Thor Taylor H tau leptons. The method is expected to have wider → ττ applications in other physics searches. PhD student The search for the Higgs boson decaying into Brian Le, with Jennens and Zanzi, pioneered a pairs of tau leptons is the most sensitive analysis multivariate approach for estimating the background for discovering and measuring the Higgs boson events from production of two vector bosons. coupling to fermions. Preliminary results released Elisabetta Barberio edited the paper submitted to in 2013 showed strong evidence for Higgs boson Physical Review D. decays into tau leptons. This result was updated CoEPP researchers are also fully committed to the in 2014, based on the full dataset collected by the ATLAS H analysis for the current period of ATLAS experiment during the first period of LHC → ττ LHC data taking. The sensitivity for a discovery at data taking, corresponding to about 5 fb–1 of proton– 5 standard deviations is expected to be reached proton collisions at a centre-of-mass energy of 7 TeV in Run 2. Beginning in 2015, Barberio took on the and about 20 fb–1 at 8 TeV. The updated result (JHEP role as convenor of the analysis team. PhD student 4, 117 [2015]), shows a clear excess of events, with Laurence Spiller developed an improved multivariate a significance of 4.5 standard deviations above the analysis of the Run 2 data in the fully hadronic final background-only hypothesis. This is the strongest state, using new topological variables he developed evidence so far for the Higgs boson coupling to (JHEP 03, 027). Zanzi and PhD students Brian Le fermions. and Pere Rados contributed to the data acquisition Under the hypothesis that the Higgs boson is software for events with hadronically decaying taus produced and decays to tau leptons, the measured and to calibrating the energy measurement of such cross-section is 1.4 ± 0.4 times the one predicted particles. Zanzi is also leading the design of the by the SM, and the measured Higgs boson mass is measurement of the Higgs boson charge parity (CP)

20 RESEARCH ANNUAL REPORT

quantum number in the Higgs boson decays into an excess of events corresponding to 2.1 + 1.4 − 1.2 tau leptons. This is a complex analysis because of times the SM expectation were observed (Phys. the difficulty in selecting the signal events and the Lett. B 749:519–541 [2015]). In 2016, the preliminary need for a precise reconstruction of the tau lepton analysis of the first 13.2 fb–1 of proton–proton data decays. Nonetheless, this analysis will be one of the collected at 13 TeV confirmed the result, measuring most sensitive measurements for the Higgs boson CP a ttH cross-section 2.5 + 1.3 − 1.1 higher than the quantum number, with important implication for the SM prediction (ATLAS-CONF-2016-058), as shown indirect search for physics beyond the SM. in Figure 1. PhD student Marco Milesi, Barberio and Zanzi worked on determining the background H → WW events with mis-reconstructed leptons in events with two leptons with same electric charge – the most In Melbourne, Takashi Kubota and PhD student Pere sensitive final state. They are now analysing the full Rados continue to lead efforts to measure the cross- dataset collected in 2016, which is 2.5 larger than the section of Higgs bosons produced in association with one already analysed, to provide the first evidence a W boson in the final state where the Higgs boson of the ttH production. Milesi, Barberio and Zanzi decays into a pair of W bosons (WH → WWW). This are re-optimising the trigger selection strategy and channel allows Higgs boson couplings to W bosons improving the background estimate to reach even to be directly measured. Kubota was the coordinator higher sensitivities. of the WH → WWW analysis group and edited the first publication from the H → WW group that was H→ γγ, Zγ based on 13 TeV data (ATLAS-CONF-2016-112). So far, this has been the only publication in the H → WW Decays into pairs of photons are particularly decay with 13 TeV data and is therefore significant attractive for studying the properties of the Higgs for Higgs boson studies in ATLAS. Rados lead the boson, thanks to the high photon reconstruction and WH → WWW analysis in the final state with three identification efficiency and the excellent photon leptons, and was in charge of outlining the Run 2 energy resolution at ATLAS. CoEPP researchers in trigger strategy for all H → WW analyses. Sydney are taking leading roles in searches for both the SM Higgs boson and for a high mass resonance In Adelaide, Paul Jackson and PhD student Jason in decays to photons and other bosons. Oliver also joined the H → WW efforts, working on signal extraction methods and characterisation for Jin Wang has been responsible for generating the H → WW events produced by gluon fusion. and validating the simulation used in the H → γγ analyses. Wang has also been one of the leading ttH → leptons contributors in measuring the Higgs boson production cross-section by vector boson fusion CoEPP researchers in Melbourne are making (VBF) using the H → γγ decay. crucial contributions to the search for Higgs boson production associated with top quark With collaborators at IHEP in China, Wang pairs (ttH) in leptonic final states. The search for developed a multivariate method to maximise this rare Higgs boson production mode is one of the sensitivity of the VBF H → γγ signal against the ATLAS flagship analyses in the LHC Run 2. nonresonant backgrounds, including events with The observation of ttH events provides a direct misidentified photons, and resonant backgrounds, measurement of the Higgs boson coupling to top such as H → γγ events produced by gluon fusion. −1 quarks, with significant implications for searches Preliminary results on the first 13.3 fb of Run 2 for new physics beyond the SM. In the analysis of data have been presented at ICHEP 2016 (ATLAS- the 20.3 fb–1 of 8 TeV data, in which PhD student CONF-2016-067). In addition to producing the Francesco Nuti, Barberio and Zanzi were involved, cross-section measurement, Wang is working on Figure 1 Best fit values of the ttH cross section in units of SM prediction by final state category and combined.

21 RESEARCH ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

measurements of Higgs boson properties, such as its of this paper (ATLAS-CONF-2016-044) and led spin and CP quantum numbers. He contributed to the trigger studies, while Limosani was co-editor of introduction of the so-called “optimal observables”, the supporting documentation and did background variables that combine multidimensional information modelling studies. from the production and decay matrix elements in the H → γγ analyses. These variables provide Rare and exotic Higgs searches sensitivity to the spin and CP quantum numbers, as well as to higher-order operators beyond the CoEPP researchers are also involved in several SM, in an effective field theory approach. Wang searches for rare Higgs boson decays and for heavier also contributes to the search for the production of Higgs boson partners beyond the SM. WWγγ events, with one SM Higgs boson decay into In Melbourne, Zanzi has been involved in the search photons and the WW pair produced either by the for the rare Higgs boson decay into a Φ meson decay of a second SM Higgs boson or by a heavier and a photon (Phys. Rev. Lett. 117, 111802) to probe scalar beyond the SM. the Higgs boson couplings to light quarks. Zanzi Anthony Morley and Tony Limosani are two of developed the trigger algorithm that selected the 2.7 fb–1 of proton–proton data at 13 TeV analysed in the leading contributors in the search for H → Zγ this search. decays. Measurements of (or limits on) the H → Zγ decay rate can provide insight into models beyond In Adelaide, Lawrence Lee and Martin White have the SM. The decay rate can help determine whether been involved in analysing the observed excess of the new boson is the Higgs boson or a member of events with two photons with invariant mass of other electroweak singlets or triplets. Furthermore, 750 GeV in the 3.2 fb−1 of data at 13 TeV recorded the H → Zγ process is the only decay of the in 2015 (JHEP 1609, 001). They developed a model Higgs to electroweak gauge bosons yet to be for the narrow and high mass signal to be used observed. This measurement will also be able to in simulation. complement the precise measurement of the Higgs boson mass already made from measurements of the H → γγ and H → ZZ decays. Morley and Limosani are also leading the search for a high mass resonance in decays to the Z-boson plus photon final state. Preliminary results using 13.2 fb–1 of proton–proton data collected at 13 TeV were presented at ICHEP (Figure 2). Morley was co-editor

Figure 2 Distribution of the reconstructed Zγ invariant mass in events including the Z boson decays to electrons and muons. The solid lines show the results of background-only fits to the data. The residuals of the data points with respect to the fit are also shown.

22 RESEARCH ANNUAL REPORT

Higgs theory program

Introduction research areas for the future runs of the LHC, and a Researchers key motivation for planned future colliders. One of CoEPP theorists continued investigating the the most important of the couplings is that between Peter Athron the Higgs boson and a pair of top quarks, the properties of the Higgs boson in light of the Csaba Balázs experimental data from the LHC. The goal of heaviest quarks in the SM. The nature of this coupling this research is to understand the dynamics of has significance for the hierarchy problem and in Tyler Corbett various cosmological models, and has drawn the electroweak symmetry breaking and uncover new Matthew Dolan physics phenomena associated with it. Theoretical attention of a number of CoEPP researchers this year. investigations in this direction also have far-reaching Matthew Dolan, Zhao-Huan Yu and overseas Paul Jackson implications for understanding the history of our collaborators (Phys. Rev. D 94, 01525) studied Archil Kobakhidze universe. The observed dominance of matter over possible LHC measurements of top-quark couplings antimatter and hence, ultimately, our existence, may to additional Higgs bosons that may exist in several Ning Liu indeed be determined by the properties of Higgs models beyond the SM. Archil Kobakhidze, Lei Wu Anthony Williams boson interactions. and Jason Yue (JHEP 1604, 011) studied alterations Lei Wu Among the key research directions of the CoEPP in the same top-Higgs couplings and in Higgs Higgs theory program are: self-couplings, and their possible relationship with Zhao-Huan Yu the matter–antimatter asymmetry of the universe. • theoretical studies of various strategies to These models may be constrained through future measure the Higgs boson couplings at the LHC LHC measurements, as was further explored by the Students and future colliders same authors, with Ning Liu, in a more recent paper Somasuntharam • model building that allows electroweak (in press with JHEP). Many models beyond the SM Arunasalam symmetry breaking to be placed within a more predict the existence of charged Higgs bosons. New complete and consistent theoretical framework strategies to search for these at the LHC have been Dylan Harries • uncovering subtle cosmological and presented by Li, Riley Patrick, Pankaj Sharma and Cyril Lagger astrophysical manifestations of Higgs physics. Anthony Williams (JHEP 1611, 164). Shelley Liang In 2016, CoEPP researchers obtained a number of Planning is already underway within the particle interesting results in these areas. physics community for future colliders, and CoEPP Adrian Manning researchers have been active in studying the Patrick Riley physics possibilities such facilities would offer. Yu Higgs collider et al. (Phys. Rev. D 93, 105315) studied how a future Marco Santoni electron–positron collider could constrain models of phenomenology Pankaj Sharma electroweak baryogenesis in a model-independent The precision characterisation of the properties way. Csaba Balázs, as part of a larger international Jason Yue of the Higgs boson is one of the most important effort (to appear in the European Physical Journal C),

Figure 1 This figure shows the estimated production cross-section required in order to be able to discriminate between different new particles (scalar, pseudoscalar, vector or axial vector) produced in association with a pair of top quarks at the LHC, using the invariant mass of the two top quarks.

23 RESEARCH ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

has contributed to a large study of Higgs physics at how an extension of the popular two-Higgs doublet the electron–positron Compact Linear Collider. model could also be made consistent with the diphoton excess. Yu et al. (Phys. Rev. D 93, 075033) Another important Higgs coupling is to the tau also constructed an extra-dimensional model in lepton, since it may be the only leptonic Higgs which the resonance appeared as a singlet scalar coupling measurable at the LHC. This coupling is particle. particularly challenging because of the decaying tau leptons. Two groups from CoEPP – Andrew Fowlie Two other significant papers were on constraints and collaborators (in press with Nucl. Instrum. Meth.) on the putative particle at 750 GeV. One was by Yu and Li and Williams (Phys. Rev. D 93, 075019) – have and collaborators (Nucl. Phys. B 909, 43), which proposed new methods to reconstruct the Higgs quantified the effects of the wide variety of searches boson mass in such decays using advanced statistical for DM on scenarios capable of explaining the techniques. Finally, Dolan et al. (JHEP 1607, 039) excess. Another paper, by Peter Athron et al. (Eur. have studied the collider signatures of a simplified Phys. J. C 76, 516), undertook a detailed analysis of model incorporating a new singlet scalar field and its a large number of theoretical scenarios, using the relation to effective field theory approaches. FlexibleTools framework to correct a number of errors and misconceptions in the literature. New theory models and ideas Fowlie et al. (JHEP 1608, 100) studied the naturalness of the recently proposed relaxion solution of the An area of particular excitement electroweak hierarchy problem. Using a Bayesian statistical approach, they argue that the SM is in the high-energy physics actually favoured over the relaxion because of the community early in 2016 was extensive fine-tuning the relaxion involves. the emergence of a “bump” in Athron and collaborators (Comput. Phys. Commun. 202, 113) have been studying precision predictions the diphoton mass spectrum of the Higgs boson mass in several different observed at both the ATLAS and theories of beyond the SM physics, including the CMS experiments. next-to-minimal supersymmetric SM (NMSSM) and an effective field theory context (JHEP 1701, 079), This possible signal of new physics prompted a which have resulted in public codes being made swift response from several CoEPP researchers available as part of the FlexibleTools framework. in the form of papers, most of which described Athron et al. have also been studying the detailed Higgs phenomenology of the E -extended minimal building new models to explain the apparent 6 supersymmetric SM (E SSM) in a series of papers excess, while others focused on the constraints from 6 previous measurements. (Phys. Lett. B 760, 19; JHEP in press). Lei Wu and collaborators (Phys. Lett. B 759, 191) showed how anomaly-mediated SUSY breaking could accommodate a Higgs-like particle, which could explain the diphoton signal, while simultaneously explaining the apparent anomaly in the magnetic moment of the muon. Further work by Wu et al. (Phys Lett. B 756, 309) demonstrated

Figure 2 This figure shows the current constraints (in the left-hand panel) from the LHC on anomalous couplings between the top quark and the Higgs boson, and in the right-hand panel the prospects for improvement by including data from the ongoing Run 2.

24 RESEARCH ANNUAL REPORT

Neutrino theory program

Introduction generation is incorporated. Various scenarios were Researchers examined in these papers. While the experimental discovery of neutrino flavour McDonald and collaborators also examined Yi Cai transformations and oscillations – the subject of the “scotogenic” and scale-invariant models (JHEP 1606, Kristian McDonald 2015 Nobel Prize in Physics – proves that neutrinos 182), with some of this work involving PhD student have mass and quantum mechanical mixing, the Adrian Manning (Phys. Rev. D 94(5), 053005). The Michael A Schmidt mechanism by which they acquire those masses and term “scotogenic”, coined by Ma, refers to neutrinos Raymond Volkas mixing parameters remains unknown. In particular, gaining their masses through interactions with DM. the fact that neutrino masses – though nonzero – are Scale invariance is the hypothesis that all particles, so much smaller than the other types of leptons including the Higgs boson, are massless at the Students and quarks suggests that they obtain their masses classical level. Thus, the origin of all elementary in a different manner. One approach to explain this particle masses, not just those of neutrinos, is Jackson Clarke encompasses the so-called “seesaw models”, where proposed to be purely quantum mechanical. Some Joshua Ellis the neutrino masses are inversely proportional to a of the new particles required by these models can be high mass scale of new physics. searched for at the LHC. John Gargalionis Another possibility, which was the focus of much The exotic particles in these models can also Adrian Manning of the CoEPP research in 2016, is that neutrino sometimes be used to achieve the grand unification masses are generated “radiatively”. This means that of the strong, weak and electromagnetic interactions. neutrinos are massless at the classical level, but This prospect was analysed by Schmidt and obtain masses when the quantal effects of virtual collaborators (JHEP 1609, 111). They delineated the particle exchange are considered. Some of these cases where unification can be achieved, and where virtual particles must be exotic, meaning not in the it is impossible. SM. Such particles can potentially be produced at the LHC, a topic of longstanding interest to both In ongoing work that will be completed in early 2017, theorists and experimentalists at CoEPP. Cai, Schmidt and Volkas have been working with PhD student John Gargalionis to examine an interesting In 2016, a strong focus of the theoretical research possible connection between radiative neutrino mass effort was on combining radiative neutrino mass models and certain experimental anomalies in the generation with models of DM. physics of B mesons. Returning to seesaw models, Cai and Volkas, working Research with PhD student Jackson Clarke and collaborator Yanagida (Institute for the Physics and Mathematics Kristian McDonald and collaborators examined the of the Universe, Japan), developed an E6-inspired prospect of accommodating “minimal DM” in such scenario where the seesaw mass scale of new models (Phys. Lett. B 757:399–404). This topic was physics can be brought down to levels relevant independently also considered by Yi Cai and Michael for the LHC (Phys. Rev. D 94(3), 033003). This is Schmidt (JHEP 1605, 028). Minimal DM, in its original interesting because, in the standard seesaw theories, formation, is guaranteed to be stable because of the scale of new physics is inaccessible to the LHC. its unusual quantum numbers under the SM gauge The detailed phenomenology of this model was interactions. This feature becomes jeopardised examined in the MSc thesis by Joshua Ellis. when the extra physics for radiative neutrino mass

Figure 1

The E6-inspired pseudo-Dirac seesaw model provides potential explanations for the di-photon excess. The pseudo scalar pairs produced via s-channel singlet will decay to highly collimated (and displaced) photon pairs which will be reconstructed a single prompt photons.

25 RESEARCH ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

Precision tests of the Standard Model

Researchers Introduction Monte Carlo event generators with free parameters that can be constrained by such measurements. Kevin Finelli The SM is the theory describing all known An accurate description of low energy, strong fundamental particles and their interactions through interaction processes is essential for simulating the Mark Kruse (Duke) electromagnetic, weak, and colour forces. It assumed effects of multiple proton–proton interactions at Anthony Morley its current form in the mid-1970s and has achieved high instantaneous luminosity in hadron colliders. remarkable success by predicting the existence of The importance of this measurement cannot Peter Skands weak gauge bosons, the top quark, the tau neutrino be overstated because it forms the basis for all Kevin Varvell and, most recently, the Higgs boson. measurements undertaken at 13 TeV by elucidating the underlying event and the measurement of Jin Wang With no evidence of physics beyond the SM in all systematic uncertainties arising in charged accelerator-based collider experiments, more particle tracking. attention is turning to both precision measurements Students of, and searches for, SM processes. This quest is As convener of the ATLAS Minimum Bias@13 TeV motivated by the potential for new physics to task force, Anthony Morley led this measurement Doug Davis (Duke) perturb their rate and characteristics. Importantly, within ATLAS. Results were published in Physics Carl Suster because they form the backgrounds to many Letters B (Phys. Lett. B 758, 67) and the European searches, precise measurements of SM processes are Physical Journal C (Eur. Phys. J. C 76, 502). an essential task of the LHC physics program. In 2016, two SM measurements were completed and These measurements, together have been submitted to, or been accepted by, high- with previous results, shed light impact physics journals; they are described below. on the centre-of-mass energy Tests of models of low dependence of charged particle energy QCD multiplicities, which has been poorly constrained in the past. The measurement of the multiplicity and kinematic distributions of inclusive charged particles in proton– The distributions seen in Figure 1 are measured with proton collisions provides insight into the strong tracks from charged particles, corrected for detector interaction in the low energy, non-perturbative effects, and are presented as inclusive inelastic region of quantum chromodynamics (QCD). Particle distributions. This measurement provides a direct interactions at these energy scales are typically test of the PYTHIA8 MONASH model pioneered by described by QCD-inspired models implemented in Peter Skands from the Monash node.

Figure 1 Charged particle distributions in pp interactions measured with the ATLAS detector at the LHC.

26 RESEARCH ANNUAL REPORT

AIDA at 13 TeV Single top-quark

The An Inclusive Dilepton Analysis (AIDA) project measurements at 13 TeV includes the Sydney node and partner institute In collaboration with scientists from Bonn University, Duke University. AIDA is well established in Kevin Finelli, Carl Suster and Jin Wang have made CoEPP’s research program and in ATLAS. The first the first measurement of the production cross- measurement made by the group, “Simultaneous section for a single top quark in association with a measurements of the top-quark pair, W-boson pair, W boson at a collision energy of 13 TeV. This analysis and Z boson decay to tau-pair production cross- was first presented at ICHEP 2016 in Chicago, United sections in pp collisions at collision energy 7 TeV with States, and a preliminary result has since been the ATLAS detector”, is the basis for current efforts. submitted to JHEP. These efforts are advancing the AIDA technique to further improve the SM tests, including measuring Since October 2016, Finelli has served as convener the production of a single top quark in association for the single top-quark group in ATLAS, overseeing with a W boson, which exploits Centre expertise analysis activities and ensuring high-quality in the study of single top-quark physics; and using publications are prepared by the group. differential cross-section measurements to extend the type of analysis reported in JHEP 06, 100 (2015), “Differential top-antitop cross-section measurements Figure 2 as a function of observables constructed from Measurement of the final-state particles using pp collisions at 7 TeV in the cross-section for ATLAS detector”. producing a W boson in association with a single top quark in pp collision energy 13 TeV with ATLAS.

27 RESEARCH ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

Dark matter

Researchers Introduction Dark matter and unitarity

Peter Athron The identity of DM, the mysterious substance CoEPP theorists have made leading contributions that contributes most of the matter content of to the development of self-consistent or physically Csaba Balázs our universe, is one of the most longstanding and well-behaved descriptions of DM interactions, with Elisabetta Barberio pressing problems in particle physics and cosmology. particular focus on the requirements of gauge The energy density of DM in the universe is five times invariance and perturbative unitarity. Nicole Bell greater than that of ordinary matter, yet we have very Theorists at the Melbourne and Sydney nodes Giorgio Busoni little information about its fundamental properties. collaborated on a project related to unitarisation of While many well-motivated particle physics theories Yi Cai effective field theory amplitudes for DM searches. predict a DM particle of some sort, the challenge is Nicole Bell, Giorgio Busoni, Archil Kobakhidze, Noel Dawe to identify which of these theories may be correct. David Long and Michael Schmidt proposed a new Excitingly, we have reached an era where the Matthew Dolan approach to the LHC DM search analysis within sensitivity of current experiments is sufficient to the effective field theory framework by using the Robert Foot substantially test one of the most popular and well- K-matrix unitarisation formalism. This approach motived classes of DM theories: weakly interacting Paul Jackson allows a reasonable estimate of the DM production massive particles, or WIMPs. cross-section at high energies to be obtained, and Archil Kobakhidze CoEPP researchers have made a substantial hence reliable experimental bounds determined, Jinmian Li contribution to DM research, including development without running unphysical effects such as of DM theories, phenomenological work on DM perturbative unitarity violation. The LHC mono-jet Tong Li searches and signals, and analyses of ATLAS process was used to illustrate this technique (JHEP Roman Nevzorov experimental data for mono-X and other DM signals. 1608, 125). Anthony Thomas Bell, Cai and Leane studied indirect detection Research signals in a self-consistent hidden U(1) model, in Francesca Ungaro which a DM candidate interacts with both a dark Phillip Urquijo gauge boson, and a dark Higgs field. The dark Higgs Dark matter searches at the LHC provides a mass generation mechanism for the Raymond Volkas dark-sector field, and is required for the model to CoEPP researchers made important contributions to Martin White be physically well behaved to high energies. They collider DM research. found that the inclusion of two mediators opens up Anthony Williams CoEPP students Amelia Brennan and Mille McDonald a new, dominant, s-wave annihilation channel that Zhao-Huan Yu worked with international collaborators Johanna is missed in the usual single-mediator simplified Gramling and Thomas Jacques to determine model approach (JCAP 1608, 001). In a related constraints on DM simplified models using the LHC work, Bell, Cai and Leane examined the impact of Students Run I dataset. Mono-jet, mono-Z (leptonic) and the dark-sector mass generation mechanism. They mono-W/Z (hadronic) channels were considered demonstrated that the DM interaction types, and Ankit Beniwal (JHEP 1605, 112). hence the annihilation processes relevant for relic Amelia Brennan density and indirect detection, are strongly dictated CoEPP postdoc Francesca Ungaro worked on the by the mass generation mechanism chosen for the Jackson Clarke search for DM-associated production with bottom dark-sector particles, and the requirement of gauge quarks, using 13 TeV proton–proton collisions at the invariance (to be published in JCAP in early 2017). Ben Geytenbeek ATLAS detector at the LHC (ATLAS-CONF-2016-086). Dylan Harries Ungaro also searched for a supersymmetric partner Dark matter model building of the top quark (in the jets plus mixing energy final Rebecca Leane state) in 13 TeV ATLAS data. This work also involved CoEPP student Jackson Clarke worked with Raymond David Long an interpretation of these results for the case of Volkas to propose a nonsupersymmetric technically DM-associated production with top quarks (ATLAS- natural model that accounts for neutrino masses, Millie McDonald CONF-2016-077). baryogenesis, the strong CP problem and DM. In Filip Rajec Nicole Bell, Yi Cai and Rebecca Leane studied this paper, DM is identified with the invisible axion in the context of a model that also explains neutrino Andre Scaffidi mono-W signals for DM production at the LHC in the context of self-consistent simplified models, and masses and the matter–antimatter asymmetry Isaac Sanderson projected the future reach of the LHC for the leptonic of the universe in a technically natural way with respect to nongravitational interactions (Phys. Rev. D Sunny Vagnozzi (mono-lepton) and hadronic (mono fat jet) decays of the W boson. They also examined the ability of a weak 93, 035001). isospin-violating effect to enhance signals, in models Combining neutrino mass generation and a DM with underlying gauge invariance (JCAP 1601, 051). candidate in a unified model has always been

28 RESEARCH ANNUAL REPORT

Figure 1 Spin-1 mediated mono-W dark matter signal at the LHC.

intriguing. CoEPP researchers Cai and Schmidt Yu collaborated with international colleague Tim revisited the class of RνMDM models, which Tait on a project involving triplet-quadruplet DM, in incorporate minimal DM in radiative neutrino which the SM particle content was extended by one mass models based on the one-loop ultraviolet fermionic triplet and two fermionic quadruplets. This completions of the Weinberg operator (JHEP resulted in a minimal realistic ultraviolet-complete 1605, 028). model of electroweak-interacting DM, in which the DM interacts with the Higgs doublet at tree Peter Athron, Dylan Harries, Roman Nevzorov and level through two kinds of Yukawa couplings. The Anthony Williams explored the DM phenomenology conditions under which the lightest new particle is of E -inspired SUSY models that have an SM-like 6 neutral were examined, and the regions of parameter Higgs and evade current LHC limits on new states. space for which the correct density is saturated These models allow striking new signatures that were identified. While precision electroweak may be observable during Run 2 of the LHC, and measurements, searches for DM scattering with can be substantially tested in future direct-detection nuclei, and DM annihilation place important experiments (Phys. Lett. B 760:19–25; JHEP 1612, 128). constraints on this mode, they leave open a viable CoEPP students Ankit Beniwal and Filip Rajec range for a thermal relic (JHEP 1603, 204). – under the supervision of Martin White and Yu also collaborated with Xiang, Bi and Yin on a Anthony Williams, plus international collaborators simplified scenario in the NMSSM, in which only Christopher Savage, Pat Scott and Christoph the singlino and higgsinos are light and other Weniger – have performed the most comprehensive superpartners are decoupled. The future sensitivities exploration to date of Higgs portal DM scenarios. of direct and indirect DM detection experiments These are arguably the simplest possible were examined, together with LHC searches in explanations of DM, in which one adds a single new the 3-lepton and 2-lepton channels (Phys. Rev. D particle to the SM, chooses a spin, and allows the 94, 055031). new particle to interact only with the Higgs boson. The team studied three different DM spins in the framework of effective field theory, and applied all Dark matter indirect detection known constraints from particle and astrophysics Indirect searches for DM can be done by looking experiments. They also studied future projections for the decay products of DM annihilation in distant from forthcoming astrophysics experiments astrophysical objects. In the case of DM decays (Phys. Rev. D 93(11), 115016), including the Cherenkov to muons, a small correction to the photon flux Telescope Array (CTA), which Australia recently arises from radiative muon decay, a rare but well joined (including CoEPP members Csaba Balázs understood decay mode of the muon. CoEPP student and Martin White). Andre Scaffidi, with Jinmian Li, Martin White, CoEPP postdoc Zhao-Huan Yu collaborated with Anthony Williams and international collaborators Xiao-Jun Bi, Qian-Fei Xiang and Peng-Fei Yin on Chris Savage and Katherine Freese, were the first to a project in which the 750 GeV diphoton excess study this effect within a DM context, and studied observed at the LHC was linked with DM. The the implications for both gamma ray and positron diphoton was explained in the framework of effective observations. The results have important implications field theory, assuming the diphoton resonance is for our understanding of the positron excess a scalar (pseudoscalar) particle. It was found that observed by the AMS-02 experiment (Phys. Rev. D the large production rate and the broad width of 93, 115024). this resonance are hard to simultaneously explain if An excess of gamma rays coming from the galactic only visible final states are considered. Therefore, an centre, and consistent with DM annihilation, has been invisible decay channel to DM was strongly favoured previously observed by the Fermi-LAT experiment, by the diphoton excess with a broad width, given a exciting much interest in the particle physics large coupling of the new scalar to DM. By examining community. However, 2016 was the year in which constraints on the parameter space of this scenario, astrophysical explanations that do not require DM it was found that DM searches can exclude a large became increasingly convincing. Work by CoEPP portion of the parameter regions, accounting for the member Martin White in collaboration with Roland diphoton excess with a broad width (Nucl. Phys. B Crocker and a number of other astrophysicists 909:43–64). demonstrated that a mechanism that explains the

29 RESEARCH ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

generalised positron excess seen in our galaxy might collaborators Pat Scott, Aldo Serenelli and also explain the Fermi gamma ray excess through Aaron Vincent, investigated the effects of DM the production of the millisecond pulsar population with nontrival electromagnetic dipole moments that is now the favoured astrophysical explanation on the structure of the solar interior. A range of (arXiv:1607.03495). helioseismology observables were used to derive new limits on electromagnetic dipole moment Balázs and Tong Li examined the ability to extract DM (arXiv:1610.06737). DM properties from indirect detection data, using different interstellar emission scenarios proposed CoEPP theorist Robert Foot studied dissipate by the Fermi-LAT Collaboration to explain the DM. This is where the self-interactions of DM Galactic Center gamma ray excess. They found that particles are strong enough to have important the properties of DM extracted from the data are astrophysical effects. highly sensitive to the modelling of the interstellar Foot and past CoEPP MSc student Sunny Vagnozzi emission because of experimental and theoretical examined the missing satellite problem in the uncertainties (arXiv:1609.00113, submitted to JCAP). context of dissipative DM models. The suppression Balázs and Li also performed a comprehensive of small-scale structure arises in these models statistical analysis of the AMS-02 electron and as a result of dark acoustic oscillations and dark positron fluxes, and the antiproton-to-proton ratio diffusion damping at early times, just before the in the context of a simplified DM model. They found epoch of matter radiation equality. Such models that AMS-02 observations are not only consistent can also potentially explain the puzzle of the planar with the DM hypothesis within the uncertainties, but distribution of satellite galaxies around the Milky that adding a DM contribution improves the fit to the Way and Andromeda (JCAP 1607, 013). data (JHEP 1605, 033). Foot and PhD student Jackson Clarke studied novel Balázs worked with the CTA collaboration to implications of “plasma DM” for direct detection examine prospects for indirect detection with the experiments. They pointed out that such DM CTA. In this work, sensitivity predictions for DM can produce keV electron recoils observable in searches were given on various targets, taking into current experiments, and may possibly explain account the latest instrument response functions the longstanding DAMA annual modulation signal expected for the CTA and systematic uncertainties (JCAP 1601, 029). from the backgrounds. The conclusion was that, Foot examined the effect of dissipate DM on the by observing the centre of the Galactic Halo, the rotation curves of dwarf galaxies and proposed CTA will have a unique chance of discovering a simple analytic formula for the DM density weakly interacting massive particles with masses distribution around these galaxies. The analytic between a few hundred GeV and a few tens of TeV formula was motivated by dissipative DM dynamics, (PoS ICRC2015, 1203). and was shown to provide a reasonably good fit to the rotation cure measurements of LITTLE THINGS Astrophysical constraints on (Local Irregulars That Trace Luminosity Extremes, dark matter properties The HI Nearby Galaxy Survey) dwarf galaxies (JCAP 1607, 011). CoEPP student Ben Geytenbeek, under the supervision of Soumya Rao, Martin White and Anthony Williams, plus international

Figure 2 K-matrix unitarisation remedies the unphysical large enhancement of the monojet process in effective theories. All points on the red dashed Thales circle are mapped to the same point on the Argand circle.

30 RESEARCH ANNUAL REPORT

Searching for supersymmetry

Introduction Sujeet Akula studied the variety of simplified models Researchers that are relevant in scenarios of supergravity grand The SM describes all known particles and their unification, and studied the phenomenology at the Sujeet Akula interactions, and explains a vast number of LHC for Run 2 and in direct searches for neutralino Peter Athron experimental observations from subatomic collisions DM (JHEP 1501, 158 [2015]). to the microscopic workings of the universe. CoEPP researchers are studying models beyond Csaba Balázs The SM particle content was completed with the minimal extensions to the SM arising from an Matthew Dolan discovery of the Higgs boson. However, the presence elegant and unified picture at high energies, which Paul Jackson of the Higgs particle also creates a serious problem. are well motivated and have exciting consequences According to the SM, the mass of the Higgs boson for low energy phenomenology. In an ongoing Archil Kobakhidze is affected by physics that is separated from it by project, CoEPP researchers Peter Athron, Anthony Lawrence Lee 15 orders of magnitude, thus creating a problem Thomas, Sophie Underwood and Martin White are of “naturalness”. combining LHC measurements of the Higgs boson Jinmian Li and mass limits on new supersymmetric particles for SUSY is an important theory in particle physics, a complete search across parameter space for the Ning Liu which is being pursued in the hope of explaining E SSM to identify scenarios compatible with Higgs 6 Roman Nevzorov such theoretical dilemmas. SUSY offers a simple properties, relic density, direct DM searches and solution to the naturalness problem by pairing beyond (arXiv:1611.05966). Andreas Petridis all standard particles with superpartners. This Pankaj Sharma mechanism, in turn, relies on known symmetries of In other ongoing projects with related models, the SM to shield the Higgs mass from high-energy Athron, Dylan Harries and Anthony Williams have Anthony Thomas investigated fine-tuning in the E SSM and other U(1) corrections. SUSY also provides a DM candidate, 6 Francesca Ungaro currently lacking in the SM. It is a unified framework extensions of the minimal supersymmetric Standard for all forces and matter, including gravity. Model (MSSM). Athron, Harries, Roman Nevzorov Martin White and Williams applied state-of-the-art techniques to calculate the relic density of DM, as well as the Anthony Williams Research mass of the Higgs boson and new particles predicted Lei Wu by the model, and presented benchmark scenarios Theoretical models with phenomenology for future testing (Phys. Lett. B 760:19–25). Students Archil Kobakhidze, Ning Liu, Lei Wu and collaborators The same authors explored higgsino DM in a string- have studied the phenomenology of closing the light Damir Duvnjak inspired model (JHEP 1612, 128), showing a large stop (the supersymmetric partner to the top quark) parameter space where it can naturally explain the Dylan Harries available phase space in natural SUSY scenarios at measured relic density, but also demonstrated that the LHC (Phys. Lett. B 755, 76). Jason Oliver the Large Underground Xenon (LUX) direct detection Wu has further studied measurement of a singly experiment has a large impact on scenarios with Anum Qureshi produced stop to probe new physics (Phys. Rev. lighter phenomenology by heavily constraining well- Marco Santoni D 93(3), 035003). In a different environment, tempered neutralino DM proposed by Arkani-Hamed, produced through the collision of high-energy Delgado and Giudice. Abhishek Sharma electron and positron pairs, Wu and collaborators Athron and collaborators compared Higgs mass Matthew Talia have looked at the phenomenology of SUSY effects predictions of NMSSM spectrum generators, in the production of Higgs bosons. This work will Sophie Underwood identifying the origin of the differences and be an important input to future electron–positron demonstrating much larger uncertainties than had Graham White machines such as the CERN Future Circular Collider previously been assumed (Comput. Phys. Commun. (FCC-ee) or the proposed Circular Electron Positron 202, 113–130). Athron and collaborators also Collider in China. developed GM2Calc, which currently performs the Matthew Dolan and collaborators used simplified most precise estimate of the anomalous magnetic models as a useful way to characterise new physics moment of the muon in the MSSM (EPJC 76(2), scenarios for the LHC, and studied a variety of 62), an “observable” where current measurements approaches to combine kinematic variables (JHEP indicate evidence for physics beyond the SM that 1608, 038). Dolan also worked on a likelihood could be explained by SUSY. analysis of SUSY SU(5) grand unification theory Athron further proposed and constructed a models, adding new constraints from searches new method to calculate the Higgs mass in for direct sparticle production at 13 TeV in the jets supersymmetric models (arXiv:1609.00371v3). He and missing transverse momentum final state – showed that this method leads to precise predictions performed by CoEPP experimental collaborators both when the new physics scale is high and – and in long-lived particle searches.

31 RESEARCH ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

when it is very close to the electroweak scale. The Experimental searches calculation was implemented using FlexibleSUSY (also developed by Athron and collaborators) to CoEPP has played an active role in ATLAS make more precise predictions of Higgs masses in a SUSY searches. number supersymmetric models and shed new light Jackson, with collaborators at Harvard University, on the uncertainties in Higgs mass predictions in the has developed a new kinematic basis to design minimal model. more natural, physics-inspired variables that permit Jinmian Li and Williams investigated light NMSSM more sensitive extraction of signals through a wide pseudoscalar states with boosted ditau tagging range of mass splittings. The method – recursive (JHEP 1605, 100). Pankaj Sharma and collaborators jigsaw reconstruction – has been pioneered by investigated the discovery prospects, through Adelaide CoEPP members, led by Jackson. The Higgs pair production with large missing transverse reconstruction code is now available for public momentum at the LHC, of an R-parity violating use at Restframes.com. Jackson, Lee and Santoni SUSY model with a higgsino lightest supersymmetric presented the uses of the recursive jigsaw technique particle, motivated by naturalness and the at the 2016 SUSY conference. This method has been generation of neutrino masses (JHEP 1612, 062). applied to analyses within the ATLAS collaboration in searches for decays of top squarks and for gluino Martin White is the co-leader of the GAMBIT and light squark pair production in final states free collaboration, a statistical-fitting team with many of charged leptons. Considerable improvement in the international particle physicists, astrophysicists and region where the mass difference between parent statisticians, including a number of current CoEPP and missing particle is small has been seen. members (Athron, Balázs, Fowlie and Jackson). The GAMBIT code was completed during 2016, and the Jackson, Lee, Petridis, Qureshi and Graham White first version, with its accompanying publication, will contributed to the search for the pair production of be released soon. gluinos and squarks resulting in final states enriched in hadronic jets and missing transverse momentum. Lee and Jackson spearheaded this analysis using the recursive jigsaw variables. They also led the group of 12 researchers from Australia, Europe and the United States throughout 2016.

Figure 1 A comparison of the observed and expected event yields as a function of signal region considered in the SUSY 0-lepton analysis using the recursive jigsaw reconstruction based search. The background expectations are those obtained from the background-only fits.

32 RESEARCH ANNUAL REPORT

Petridis is the convener of the searches for SUSY Francesca Ungaro was involved in the search for top with electroweakinos (the SUSY partners of the SM squarks in the 0-lepton final state. Her focus was gauge bosons). He leads the ATLAS SUSY group to extend the SUSY search to probe generic models in searches for final states with two and three sensitive to SUSY and DM physics. leptons. The analyses pursued in this group focus Jackson and Santoni, with collaborator Christopher on the production of electroweak SUSY partners or Rogan from Harvard, submitted the paper “Sparticles “gauginos”. Damir Duvnjak, Jackson, Petridis and in motion” to Physical Review D. Santoni works with Pankaj Sharma will publish a first analysis studying Sydney colleague Wu and former Sydney graduate the trilepton final state, and dilepton production student Jason Yu to study the phenomenology in association with jets and missing transverse of compressed higgsino production, and design momentum in the context of electroweak SUSY improved analysis variables and approaches to processes with intermediate W and Z bosons. The measuring new physics effects in the Higgs boson analysis has been able to be extended by using the production channel in association with a top and recursive jigsaw reconstruction method. anti-top quark pair.

Figure 2 Observed and expected exclusion limits on the common chargino and neutralino masses. The observed limits from ATLAS Run 1 are included for comparison. Current analyses pursued by Jackson and Petridis are targeting an as yet unprobed region in the two-lepton plot.

33 RESEARCH ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

Research computing

Chief Introduction Australia-ATLAS Tier 2 grew by 280 terabytes to 1180 terabytes with the purchase of seven new Investigators The field of research computing advances rapidly. storage servers, and by 800 HS06 to 11500 HS06 The research computing (RC) team at CoEPP keeps by dedicating spare nodes from the MPI cluster to Martin Sevior abreast of innovations and developments in the field CoEPP ATLAS Tier 2 queues, thereby meeting the Anthony Williams so that CoEPP researchers can achieve their scientific experiment’s resource demands for 2016. goals and maximise their participation within scientific collaborations. Increasing storage and Infrastructure Staff computing power available to researchers is equally important and ensures that particle physics problems Lucien Boland, Research The RC team worked on many projects in can be solved in a timely manner. The RC team Computing Manager 2016 to ensure that the capability of the core manages operation of the Australian Worldwide LHC computing infrastructure reliably delivered the Goncalo Borges, Research Computing Grid (WLCG) ATLAS Tier 2 site, as well as required computing services for ATLAS and Computing Officer local computing resources. CoEPP researchers. Sean Crosby, Research In 2016 the RC team grew CoEPP’s storage and Key services were upgraded from Scientific Linux 6 Computing System compute capacity, delivered new computation to CentOS 7 in preparation for the eventual phasing Administrator and services, including the MPI cluster, and procured a out of the Scientific Linux distribution. This work Developer general purpose GPU cluster. The performance of the provided a good opportunity to migrate from the Australian ATLAS Tier 2 site in 2016 was remarkable, Jeremy Hack, eResearch XenServer virtualisation platform to the more and saw it ranked first in the world. Developer integrated CentOS KVM solution, removing the need for the dedicated Xen storage network, and paving Grid computing the way for easier and faster server deployments. The configuration management tool was upgraded The WLCG provides researchers from around the from Puppet 3 to Puppet 4, and incorporated world access to the LHC data and the computing necessary CentOS 7 system changes. The Puppet resources necessary for their analyses. The WLCG is software upgrade also allowed a change to the Git a global collaboration of more than 170 computing repository architecture so it would be more modular, centres in 42 countries, and needs to be highly and to redesign the Nagios monitoring infrastructure available and reliable to process the approximately so it would be more flexible for additional 50 petabytes of LHC data generated each year. service inclusions. The Ceph storage service was upgraded to the In 2016, the Australian WLCG latest stable release and capacity was increased Tier 2 site was available for with the addition of the retired Tier 2 DPM storage nodes, giving a total of 306 terabyte raw capacity or 99.74% of the year and had a 102 terabyte usable. reliability of 99.84%. This made it the highest ranked site of all CoEPP local computing

ATLAS Tier 2 sites around the The RC team continued to provide reliable world and marked an incredible computing resources dedicated to local CoEPP achievement by the RC team. researchers. The University of Sydney’s local storage server was replaced to provide in-warranty hardware The CoEPP Tier 2 cluster completed 105M HS06 for local home directories and data storage; and CPU hours of computation, up 35% from 2015, and the University of Adelaide received a new server delivered an additional 5% above that pledged to the to increase their local cluster’s capabilities. The ATLAS distributed computing effort. This included University of Melbourne received a new GPGPU many multi-core jobs, the successful completion of cluster, partly funded by the School of Physics Pierce which required careful batch queue configuration bequest and a collaboration with the Astronomy and fine-tuning for efficient integration into research group. This cluster will allow new and CoEPP clusters. interesting machine learning techniques to be explored by researchers.

34 RESEARCH ANNUAL REPORT

Running and upgrading the experiment

Being a member of the ATLAS collaboration provides the opportunity to not only analyse data from the experiment but to also run the experiment and perform R&D on upgrades. The ATLAS detector is arguably the most complex scientific instrument ever created, and, along with the WLCG that serves its data, requires many hundreds of people to run and maintain it.

ATLAS recognises this through its organisation being loosely broken • ATLAS Semiconductor Tracker data acquisition upgrade down into Detector Operation, Trigger, Computing and Software, Damir Duvnjak, Paul Jackson, Lawrence Lee, Mark Kruse (Duke) Data Preparation, and Physics activities. With the LHC continually • ATLAS simulation development improving to reach and extend its design goals, the detector, trigger, Andreas Petridis, Anum Qureshi computing infrastructure and software must not only be maintained, • ATLAS Software Infrastructure Team but must mirror the improvements in the LHC to simply keep up, and Antonio Limosani thereby ensure that physics outcomes are maximised. • ATLAS tau lepton energy scale In this section, we highlight roles in running and upgrading the Daniele Zanzi, Brian Le experiment undertaken by members of CoEPP. Roles associated with • ATLAS tracking studies: “Stability study of ATLAS pixel cluster physics data analyses are covered in previous sections and are not neural networks”, “Reconstruction in dense environments” included here. Roles undertaken by CoEPP members are: Anthony Morley • ATLAS Beam Spot Coordinator • ATLAS tau lepton trigger efficiency Anthony Morley Federico Scutti, Lara Mason • ATLAS Fast Track Trigger Integration • ATLAS pile-up jet suppression studies Pere Rados, Peter McNamara Thu Lhe Pham, Francesca Ungaro • ATLAS Fast Track Trigger offline software • ATLAS Inner Tracker digitisation software development Thor Taylor, Noel Dawe, Elisabetta Barberio Jason Oliver, Paul Jackson, Martin White • ATLAS Trigger online operation • ATLAS Fast Track Trigger implementation in HLT Noel Dawe, Francesca Ungaro Jason Oliver, Paul Jackson • ATLAS Fast Track Trigger upgrade electronics • ATLAS Truth Tools harmonisation Takashi Kubota Anum Quereshi • ATLAS Fast Track Trigger online software and monitoring • ATLAS SCT read-out driver data acquisition calibration studies Takashi Kubota Damir Duvnjak, Paul Jackson • ATLAS HLT development of hadronic multi-jet triggers using • ATLAS Inner Tracker strip read-out studies Razor variables Paul Jackson, Abhishek Sharma, Damir Duvnjak, Mark Kruse. Paul Jackson, Lawrence Lee

35 RESEARCH ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

Collaborations

In addition to participation in large-scale collaborations, CoEPP researchers collaborate with individuals on specific research areas and projects. These collaborative relationships involve 234 researchers from over 130 universities and laboratories in 28 countries across Asia, Europe and the Americas.

In 2016, CoEPP forged significant new relationships with major Minister Hunt was greatly impressed by international facilities. These new relationships grow bilateral relations and ensure that Australia maintains a vibrant and his visit to Fermilab and expressed his flourishing research base. strong support for high-energy physics in Australia. To further this he asked the US Minister Hunt visits Fermilab Department of Energy to invite Australia to Fermi National Accelerator Laboratory (Fermilab) is the major participate in the Fermilab program. high-energy physics laboratory in the United States. In October, Fermilab and CoEPP signed an international Cooperative Research Since 1967, Fermilab has been working to answer fundamental and Development Agreement (iCRADA) that encourages a rich questions about the universe and its origins. Scientists working at and diverse collaboration between the institutions. The aim is to Fermilab discovered three fundamental particles – the top quark, establish reciprocal visits by researchers, technical staff and students the bottom quark and the tau neutrino – and the laboratory is to collaborate on shared challenges. Potential shared activities gearing up to host the Deep Underground Neutrino Experiment include advanced theoretical physics, precision measurement (DUNE), the largest long-distance neutrino experiment in the techniques, advanced research computation methods, underground world.“This is a welcome alliance between our two organisations,” experimentation and accelerator R&D. said CoEPP Director Professor Geoffrey Taylor. “Whilst CoEPP is part of the ATLAS experiment at the LHC and Fermilab is the lead CoEPP has a vigorous research program that aligns well CMS laboratory in the US, there is a great deal that can be done on with Fermilab’s. developing techniques, tools and detector technology beyond the The signing of the iCRADA was commemorated with the visit to confines of these experiments. Also, the underground laboratory Fermilab by the Hon. Greg Hunt, Minister for Industry, Innovation and experience of Fermilab with the DUNE project finds synergy with Science. Minister Hunt was joined in the visit by Mr Michael Wood, CoEPP developments at the new Stawell underground facility.” the Australian Consul-General in Chicago.

Signing of the certificate commemorating the cooperation agreement between Fermilab and CoEPP. Left to right: Michael Wood (Australian Consul-General in Chicago), Hon. Greg Hunt (Minister for Industry, Innovation and Science), Professor Geoffrey Taylor (Director, CoEPP), Professor Marcela Carena (Head of Theoretical Physics Department and Director International Relations at Fermilab); Dr Nigel Lockyer (Director of Fermilab), Dr Mark Bollinger, (DOE Deputy Site Office Manager, Fermilab).

36 RESEARCH ANNUAL REPORT

“We’re glad to deepen our relationship with Institute of High Energy Physics CoEPP as we move forward into a new era In November, IHEP in China and CoEPP signed a memorandum of of physics research,” said Fermilab Director understanding to establish scientific exchange, collaboration and Nigel Lockyer. cooperation between the two organisations. This agreement will see scientists share their expertise and collaborate on several activities for mutually beneficial outcomes. In particular, the planned Circular Electron Positron Collider provides enormous potential for collaborative activities between the two organisations. IHEP Director Professor Yifang Wang said, “Today we established the formal collaboration. It will benefit to the development of high energy physics in both countries, especially to the future large science facilities.” IHEP is China’s premier research institute in particle physics, astroparticle physics and accelerator science. It manages a number of China’s major scientific facilities, including the Beijing Electron Positron Collider, the Beijing Synchrotron Radiation Facility and the Daya Bay neutrino experiment. “This formalisation of a partnership with IHEP is a great step for Australia. We share a great many research interests and I look forward to many years of successful collaboration with our colleagues at IHEP,” said CoEPP Director Professor Geoffrey Taylor.

Minister Greg Hunt with Dr Nigel Lockyer inspecting the Linac Coherent Light Source II experiment at Fermilab.

Professor Geoffrey Taylor, Director of CoEPP and Professor Yifang Wang, Director of the Chinese Institute of High Energy Physics (IHEP) sign a memorandum of understanding to establish scientific exchange and collaboration.

37 RESEARCH CONFERENCES AND WORKSHOPS

In addition to organising its annual scientific workshop, in 2016 CoEPP co-organised some key international physics conferences. ANNUAL REPORT

2016 CoEPP annual workshop and summer school in Torquay

The CoEPP annual workshop was held in the Victorian seaside deep-neural nets. The latter technology is used by global software town of Torquay from 15 to 29 February. Approximately 150 people companies for artificial intelligence applications (e.g. natural voice – a large proportion of Australia’s particle physics community – interactions) and sophisticated data mining. Our applications attended the combined gathering. In addition, CoEPP Partner of this technology for particle physics data analysis enable our Investigators from the University of Freiberg, the University of researchers to take a leading role in the development of the next Cambridge, the University of Geneva, the University of Pennsylvania generation of data scientists. All the presentations were at the and Duke University attended, as well as visitors Voica Radescu cutting edge of their respective topics, covering up-to-date research (Ruprecht Karls University), Ulrich Parzefall (Albert Ludwigs and developments. University) and Tyler Corbett (Stony Brook), providing a truly This was also reflected in the poster program, most notably by our international flavour to the gathering. graduate students, which showed a great variety of research at As usual, the workshop covered topics in theoretical particle physics, different levels of maturity. experimental data analysis, instrumentation and the development In addition to the strong scientific program, the event provided many of new facilities. The strong influence of astroparticle physics opportunities for social interactions and networking. In particular, on modern particle physics was evident in presentations on the the surfing lessons and “team building activities” designed by Centre topics of DM searches, the universal baryon asymmetry and the Manager David Varvel provided novel opportunities to get to know precision measurement of the age of the universe. The influence each other outside the usual academic environment. of advanced statistical analysis on particle physics was covered in talks from the GAMBIT collaboration, which aims to provide Overall, the workshop was a great success, and demonstrated the tests of phenomenological models against constraints from global maturity of the Australian particle physics community. measurements in particle physics and astroparticle physics and

Timeline of CoEPP conferences and workshops, 2016

26th International CoEPP Conference on Workshop Nuclear Physics Torquay, VIC 2016 500+ scientists 150 Adelaide, SA scientists

JAN MAR MAY JUL SEP NOV JAN 2016 2017

164 scientists 24th International Conference on Supersymmetry CosPA 2016 2016 250 international speakers Sydney, NSW 500+ people Melbourne, VIC

39 CONFERENCES AND WORKSHOPS ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

SUSY 2016

The Melbourne and Monash nodes hosted the 24th International SUSY 2016 also saw a diverse range of talks representing many Conference on Supersymmetry and Unification of Fundamental sectors of the vibrant theory community. The properties of the Higgs Interactions (SUSY16) in Melbourne during the first week of July. boson continue to be a strong motivational force, leading to new SUSY is one of the most prestigious annual meetings in theoretical results in precision Higgs mass calculations in a variety of models particle physics, and CoEPP won the right to organise it from four and studies of the alignment limit. The absence of any signal from other distinguished international institutes. This was the first time the LHC has also led to much work on “non-minimal” SUSY, which the conference was held in the southern hemisphere. goes beyond the MSSM. More than 250 eminent international speakers, academics, postdocs The conference featured an art@CMS exhibit, curated by art@CMS and students presented almost 300 talks at the conference. SUSY and Australian Synchrotron artist Chris Henschke. Highlights is held over 1 week, and is preceded by a 1-week graduate school included the world premiere of “Song of the Muons”, a “sonification” attended by about 65 PhD-level students from all over the world. of CMS muon events by Henschke and physicist Wolfgang Adam. Professor John Ellis of King’s College London delivered a public Experimental results from LHC Run 2 were reported. Summaries lecture on “The dark frontier”, to an audience of 500. from ATLAS and CMS on searches for supersymmetric particles confirmed no excesses in data recorded by the LHC at 13 TeV during CoEPP is grateful for support from the International Union of Pure 2015. These results have enabled the experiments to eclipse previous and Applied Physics (IUPAP) for conference sponsorship. limits on supersymmetric particles set by data recorded at 8 TeV.

Delegates at the 2016 SUSY conference in Melbourne.

40 CONFERENCES AND WORKSHOPS ANNUAL REPORT

INPC 2016

The 26th International Conference on Nuclear Physics was held in With considerable interest in the issue of the symmetry energy of Adelaide from 11 to 16 September. INPC is the major IUPAP class-A nuclear matter, Atsushi Tamii (Research Center for Nuclear Physics, conference in nuclear physics, and it was an honour to host it in Osaka University) explained how proton inelastic scattering might Australia for the first time. More than 500 scientists attended provide new information. With the insertion of hyperons to form from all continents. Thanks to the sponsorship from several hypernuclei now being recognised as an important field both in its sources, including CoEPP, more than 50 students were offered own right and because of its relevance to neutron stars, the review free registration. of recent progress by Hiro Tamura (Tohoku) was very informative. Turning to reactions, Angela Bonaccorso (Istituto Nazionale di Fisica The conference was opened by the Vice-President for Research at Nucleare, Pisa) and David Hinde (Australian National University) the University of Adelaide, Mike Brooks; the President of IUPAP, talked about the latest developments in their areas, with David Bruce McKellar; and the Chair of C12, the IUPAP Commission on focusing on the role of fission and fusion in the formation of Nuclear Physics, Alinka Lepine-Szily. Bruce McKellar recalled aspects heavy elements. of the history of IUPAP and its Adelaide connection, with the first president, Nobel Laureate Sir William Henry Bragg, having served as Precision studies in nuclear systems provide an important method the first Elder Professor of Physics at the University of Adelaide from to search for physics beyond the SM, and Eric Norman (LBL) 1886 to 1908. outlined the progress in double beta decay, focusing on CUORE (the cryogenic underground observatory for rare events). In addition, As usual, INPC covered all areas of nuclear physics, from structure Gertrud Konrad (Stefan Meyer Institute) described the use of cold to reactions, hadron physics, QCD, symmetries and relativistic heavy and ultra-cold neutrons as probes of new physics. ions. The latest results across these areas were presented in more than 360 talks across 11 parallel sessions, organised by 23 conveners. Developments related to QCD, the fundamental theory of the strong Each session typically began with a 25-minute invited talk, followed force, were described by William Detmold (Massachusetts Institute by 15-minute presentations. In addition, two poster sessions were of Technology), who explained the pioneering use of lattice QCD to held, with refreshments to encourage participation. calculate nuclear properties. Harvey Meyer (Johannes Gutenberg- University, Mainz) also dealt with lattice QCD, but in the context of Plenary sessions held every morning included 27 invited plenary spectral functions and transport coefficients for heavy ion reactions. talks. For the first time in the history of INPC, the number of plenary In the latter field, experimental developments were described by invited speakers exceeded 40%. There were also three plenary Camelia Mironov (MIT), ShinIchi Esumi (Tsukuba) and Tatyana presentations by the IUPAP prize winners in a very well-attended Galatyuk (Technische Universität Darmstadt/GSI). session on Wednesday morning. Details of the prize winners were reported in an earlier issue of Nuclear Physics News. This session was Hadron physics was also well represented, with an outstanding followed by the conference excursion, which offered the chance to overview of the current status of structure functions by Wally meet Australian wildlife or sample local wines. While South Australia Melnitchouk (Jefferson Lab). On the experimental side, Silvia is officially the driest state on the driest continent, the excursions Niccolai (IPN Orsay) explained the status and future prospects for were made somewhat more memorable by more than 100 mm of new information from the study of generalised parton distributions. rain, 20% of the annual rainfall! Annalisa D’Angelo (Roma2) explained the recent developments in what might be termed conventional baryon spectroscopy, with a Turning to some of the scientific highlights, Kouji Morimoto outlined number of new states discovered in the last few years. Meanwhile, the very recent discovery of element 113 at RIKEN. Although the the host of apparently exotic states in charmed systems, the so- name is not yet final, it will likely be called nihonium, reflecting the called X, Y and Z mesons, were presented by Shi-Lin Zhu of Peking country in which the discovery took place. In the field of nuclear University. structure, Sonia Bacca, from TRIUMF, described some frontiers in ab initio nuclear structure, while Witek Nazarewicz (Michigan State While it was impossible to have reports on all the major new University) outlined his view of the prospects for breakthroughs facilities, planned or constructed, in our field, the final session had in understanding nuclei. Shan-Gui Zhou (Institute of Theoretical presentations on three. Sidney Gales described the extreme light Physics, Chinese Academy of Sciences) talked about the structure of source initiative in Europe (at the Extreme Light Infrastructure – exotic nuclei. Ann-Cecilie Larsen (University of Oslo) described novel Nuclear Physics, Romania), and Abhay Deshpande explained plans techniques for constraining neutron capture rates relevant to heavy- in the United States to build an electron-ion collider to probe the element nucleosynthesis, and Rebecca Surman (University of Notre quark and gluon structure of protons and nuclei. Finally, Sunchan Dame) presented a nuclear physics solution to the puzzle of the Jeong from Korea outlined the plans and progress in relation to the r-process astrophysical site. Continuing the theme of nuclear science ambitious new rare ion facility there. The project, called RISP, will in astrophysics, Maria Lugaro (MTA Research Centre for Astronomy lead to the construction of RAON, with superb capabilities to explore and Earth Sciences, Hungarian Academy of Sciences) took us along the limits of rare, short-lived atomic nuclei. the path from cosmo-chronology to habitability. Following the usual custom, C12 met on the Saturday before INPC 2016, hearing reports on previous conferences and considering applications for the future. Most significantly, C12 decides the location of the next INPC, and INPC 2019 will be held in Glasgow.

41 CONFERENCES AND WORKSHOPS ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

On the Sunday, the IUPAP Working group on International Reports at and following the meeting suggest that INPC 2016 Cooperation in Nuclear Physics held its annual meeting, with reports was extremely successful, with delegates appreciating not only from around the world on the latest developments in nuclear the quality of the science but the experience of a very different science. With an eye to the social importance of nuclear science, country – physically and culturally – as well as the friendliness they Cynthia Keppel (JLab) presented an outstanding public lecture encountered across the city of Adelaide. It is a pleasure to thank (sponsored by the Australian Institute for High Energy Physics) on the conveners, whose tireless work contributed enormously to the hadron beam therapy on Tuesday evening. This was particularly success of the conference. timely because Australia has no hadron beam therapy centre, but hopes for up to four facilities in the near future.

Above from left: Anthony Thomas (chair of INPC2016), Alinka Lépine-Szily – chair of the Commission for Nuclear Physics (C12), Bruce McKellar INTERNATIONAL NUCLEAR PHYSICS CONFERENCE (president IUPAP), winners of the IUPAP Young Scientist Prize in Nuclear ADELAIDE, AUSTRALIA Physics: Haozhao Liang, Kara M. Lynch, Andreas Ekström, and past chair of ADELAIDE CONVENTION CENTRE 11-16 September 2016 C12 – Hideyuki Sakai. Image courtesy IUPAP Secretariat. www.inpc2016.com

Program International Advisory Committee: Committee: Nicolas Alamanos CEA Saclay Ralf Kaiser Glasgow Jurgen Schukraft CERN Mahananda Dasgupta ANU Thomas Aumann GSI & TU Darmstadt Taka Kajino Tokyo Yves Schutz CNRS, CERN Abhay Deshpande SUNY Faiçal Azaiez IN2P3 Reiner Kruecken TRIUMF John Simpson Daresbury Andrew Stuchbery ANU Jonathan Bagger TRIUMF Karlheinz Langanke Darmstadt Johanna Stachel Heidelberg Emiko Hiyama RIKEN Yorick Blumenfeld IN2P3 Alinka Lépine-Szily Sao Paulo Horst Stoecker Goethe Universitat Tohru Motobayashi RIKEN Angela Bracco Milano Bao-An Li Texas A&M Hans Stroeher FZ Jülich Anthony Thomas UofA Stanley J. Brodsky Stanford Adam Maj Polish Academy of Sciences Michael Thoennessen Michigan Wolfram Weise ECT* Philippe Chomaz CEA-Saclay Wally Melnitchouk Jefferson Laboratory Werner Tornow Duke Bing Song Zou CAS Jens Dilling TRIUMF Dong-Pil Min Seoul Vladimir Tretyak Kiev Marco Durante GSI Hugh Montgomery Jefferson Laboratory Robert Tribble BNL Rolf Ent Jefferson Laboratory Tohru Motobayashi RIKEN Piet Van Duppen KU Leuven Avraham Gal Jerusalem Berndt Mueller Duke Willem van Oers Manitoba Local Sydney Galès CNRS Witold Nazarewicz FRIB Dario Vretenar Zagreb Organising Michel Garçon CEA-Saclay Thomas Nilsson Chalmers Thomas Walcher Mainz Konrad Gelbke Michigan Yuri Oganessian JINR Xin-Nian Wang LBL Committee: Muhsin N. Harakeh Groningen Alfredo Poves UAM Wolfram Weise ECT* Sotirios Harissopulos Demokritos Achim Richter Darmstadt Eberhard Widmann Stefan Meyer Institut Michael Hotchkis ANSTO Wick Haxton California-Berkeley Karsten Riisager AARHUS Michael Wiescher Notre Dame Derek Leinweber UofA David Hinde ANU Marie-France Rivet IN2P3 Bolek Wyslouch MIT Anthony Thomas UofA Morten Hjorth-Jensen Michigan Craig Roberts Argonne Victor Zamfir ELI, Romania Anthony Williams UofA Dave Ireland Glasgow Guenther Rosner Glasgow Fülöp Zsolt ATOMKI, Hungary Ross Young UofA Rauno Julin Jyvaskyla Hiroyoshi Sakurai RIKEN James Zanotti UofA Helmut Satz Bielefeld

INPC 2016 poster. 42 CONFERENCES AND WORKSHOPS ANNUAL REPORT

CosPA 2016

The 13th International Symposium on Cosmology and Particle As a part of the conference program and in collaboration with Astrophysics (CosPA 2016) was held in the new building of Sydney Ideas, Professor Manfred Lindner delivered a public talk, the Sydney Nanoscience Hub at the University of Sydney from “Dark side of the universe”, on 29 November in the SNH Messel 28 November to 2 December 2016. CoEPP, the NSW Chief Scientist’s Lecture Theatre, which attracted an audience of 250 people. Office and the Asia Pacific Center for Theoretical Physics (South On 1 December, a joint meeting of the Asia Pacific CosPA Korea) were the major sponsors. The conference attracted Organisation Council and General Assembly confirmed Professor 164 participants from 19 countries, and was the largest CosPA Raymond Volkas as the new President of the Council. conference held. The conference has been widely considered as a great success. An The scientific program included 29 invited plenary and more than extract from Professor Yokoyama’s (former President of the Asia 100 contributed parallel session talks. Topics included various Pacific CosPA Council) letter says, “It was undoubtedly the best aspects of particle astrophysics, DM and dark energy; cosmic conference in the history of CosPA with many world-renowned microwave background radiation and large-scale structure; inflation speakers and good mixture of theory, observation, and experiments. and early universe cosmology; and gravity and gravitational waves. Congratulations, and see you in Kyoto next year!” The organisers made every effort to provide opportunities for young researchers from different countries to present their research at the conference, and strongly supported participation of female scientists.

Delegates at CosPA 2016, held in Sydney.

CosPA 2016 poster.

43 CONFERENCES AND WORKSHOPS OUTREACH AND ENGAGEMENT

Some highlights from the 2016 program are given in the next few pages. ANNUAL REPORT

Global Physics Photowalk Museum, and takes visitors on an immersive journey through the LHC at CERN’s Geneva laboratories. Exhibition CoEPP worked closely with museum curators to augment the On 25–26 September 2015, hundreds of amateur and professional exhibition with Australian content. This included parts of the ATLAS photographers went behind the scenes at eight of the world’s detector that were built at the University of Melbourne, information leading physics laboratories. Australia participated for the first time, and content regarding the development of SUPL, and the loan of a with the Stawell Underground Physics Laboratory (SUPL) allowing portable muon counter for use in talks. six photographers to take images of an underground physics In addition to Collider, the Powerhouse hosted the Sydney Science laboratory in its early stages of development. Two submissions from Festival from 11 to 21 August. As part of the program, CoEPP SUPL were among the top photos in the competition categories. partnered with the museum to offer a 2-day workshop where A permanent exhibition in Pioneer Lane in the heart of Stawell participants built a 1:50 scale model of the ATLAS detector using showcases winning entries, top photos from each participating lab LEGO®, alongside the model’s creator Dr Sascha Mehlhase, particle and images taken during the SUPL Photowalk. The exhibition was physicist and lecturer at Ludwig-Maximilians University Munich. launched in August 2016 by Dr Phillip Urquijo with help from local There was also the opportunity for festival participants to build LHC high-school students. “micro models” with LEGO®. The micro models were designed by Nathan Readioff from the University of Liverpool, and included LHC Magnets, the CMS Detector, the ALICE Detector, the ATLAS Detector “Symmetries” – art@CMS and the LHCb Detector.

“Symmetries” was the Australian premiere exhibition of works from art@CMS. It was held from 3 to 8 July at the University of Melbourne Public lectures as part of the 24th International Conference on Supersymmetry and Unification of Fundamental Interactions (SUSY 2016). CoEPP researchers and visitors gave several free public lectures and school talks during the year. Selected highlights include: Curated by art@CMS artist Chris Henschke, “Symmetries” featured • a public lecture by British theoretical physicist Professor John artworks by Michael Hoch, Alessandro Catocci and Pierluigi Paolucci, Ellis CBE FRS – “The dark frontier” and Yuki Shiraishi and John Ellis. It also included the premiere presentation of a CMS data sonification installation by Chris • a talk to 50 year 4 and 6 students at Sunshine Harvester Primary Henschke and experimental physicist Wolfgang Adam. School by David Wakeham • a talk to 400 students from years 9 and 10, and Victorian Certificate of Education physics students from Stawell and Collider exhibition and Sydney surrounding high schools by Dr Phillip Urquijo – “Searching for Science Festival dark matter at the Stawell Underground Physics Laboratory”.

The Museum of Applied Arts and Sciences hosted the Collider exhibition at the Powerhouse Museum in Sydney from 11 August to 30 October 2016. Collider was developed at the London Science

45 OUTREACH AND ENGAGEMENT ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

John Gargalionis speaks at work experience week

46 OUTREACH AND ENGAGEMENT ANNUAL REPORT

High schools program Exhibitions

The high schools program delivers opportunities for young people CoEPP had a strong year in terms of visual art exhibitions. It hosted to engage in, and develop their passion for, physical sciences at key three separate exhibitions (including one for permanent display), decision-making times in their study lives. and worked closely with the Powerhouse Museum to augment the Collider exhibition with appropriate Australian content. Work experience week Collision exhibition Year 10 students are immersed in a week-long program of tutorials, lectures and laboratory sessions. Sessions included lectures on In partnership with RiAus, selected entries from the 2015 Collision particle physics, distributed computing and the WLCG, the SM and competition were exhibited as part of the 2016 Visual Arts program DM. The week is based at the Melbourne node and run concurrently of the Adelaide Fringe Festival. The exhibition was grouped with other science streams. In 2016, the schedule included sessions into sections highlighting the diverse range of national entries, run by the Faculty of Science and a tour of the data centre at which included school students from Elonera Montessori School, Queensberry Street that houses the Australian-ATLAS Tier 2 centre. New South Wales; artists from across Australia; a family based All participants develop research posters that are presented at the in Tasmania; and an astrophysicist from Ballarat. In addition to end of the week. artworks, selected multimedia from CERN and the ATLAS Lego model were exhibited. The exhibition ran from 8 February to CoEPP organisers and participants were Nicole Bell, Innes Bigaram, 15 March at the FutureSpace Gallery in Adelaide. Lucien Boland, Giorgio Busoni, Tyler Corbett and Justin Tan.

Particle physics masterclass

The masterclass is an annual calendar highlight. First offered in 2012, students attend a day-long event of lectures and tutorials on the LHC and the SM; laboratory sessions where they analyse real ATLAS experiment data; and an ATLAS virtual visit, where participants link up with scientists at CERN, are taken on a tour of the ATLAS control room and are given the opportunity to ask questions about the largest experiment on Earth. In 2016, CoEPP ran an offsite masterclass held at South Oakleigh Secondary College. CoEPP participants were Noel Dawe, Shanette De La Motte, Johnathan Gargalionis and Cate MacQueen.

A virtual visit to CERN for the particle physics masterclass.

47 OUTREACH AND ENGAGEMENT PUBLICATIONS ANNUAL REPORT

Refereed journal articles

A Ahriche, KL McDonald, S Nasri and I Picek, “A critical analysis of L Cheng and G Valencia, “Two Higgs doublet models augmented by one-loop neutrino mass models with minimal dark matter”, Phys. a scalar colour octet”, JHEP 1609, 079 (2016). Lett. B 757:399–404 (2016). A Hayreter, X-G He and G Valencia, “Yukawa sector for lepton flavor Y Cai and MA Schmidt, “Revisiting the RνMDM models”, JHEP 1605, violating in h → μτ and CP violation in h → ττ”, Phys. Rev. D 94(7), 028 (2016). 075002 (2016). A Ahriche, KL McDonald and S Nasri, “The scale-invariant scotogenic MJ Dolan, M Spannowsky, Q Wang and Z-H Yu, “Determining the model”, JHEP 1606, 182 (2016). quantum numbers of simplified models in ttX production at the LHC”, Phys. Rev. D 94(1), 015025 (2016). A Ahriche, A Manning, KL McDonald and S Nasri, “Scale-invariant models with one-loop neutrino mass and dark matter candidates”, NF Bell, Y Cai and RK Leane, “Dark forces in the sky: signals from Z’ Phys. Rev. D 94(5), 053005 (2016). and the dark Higgs”, JCAP 1608(08), 001 (2016). C Hagedorn, T Ohlsson, S Riad and MA Schmidt, “Unification of S Mrenna and P Skands, “Automated parton-shower variations in gauge couplings in radiative neutrino mass models”, JHEP 1609, Pythia 8”, Phys. Rev. D 94(7), 074005 (2016). 111 (2016). AW Thomas and JD Vergados, “Solar neutrinos as background in Y Cai, JD Clarke, RR Volkas and TT Yanagida, “TeV-scale pseudo- dark matter searches involving electron detection”, J. Phys. G 43,

Dirac seesaw mechanisms in an E6-inspired model”, Phys. Rev. D 07LT01 (2016). 94(3), 033003 (2016). N Fischer, S Prestel, M Ritzmann and P Skands, “Vincia for hadron BHJ McKellar, “Dipole phases – topological and useful”, The Universe colliders”, Eur. Phys. J. C 76(11), 589 (2016). 4(3):4–18 (2016). SD Rindani, P Sharma and A Shivaji, “Unraveling the CP phase of RR Volkas, “Physics without force: the quantum world and top-Higgs coupling in associated production at the LHC”, Phys. Lett. topology”, The Universe 4(3):19–27 (2016). B 761:25–30 (2016). F Poignant, S Penfold, J Asp, P Takhar and P Jackson, “GEANT4 BM Dillon, DP George and KL McDonald, “Regarding the radion in simulation of cyclotron radioisotope production in a solid target”, Randall–Sundrum models with brane curvature”, Phys. Rev. D 94(6), Phys. Med. 32:728–734 (2016). 064045 (2016). P Athron, D Harries, R Nevzorov and AG Williams, “Dark matter in a T Cohen, MJ Dolan, S El Hedri, J Hirschauer, N Tran and A Whitbeck, constrained E6 inspired SUSY model”, JHEP 1612, 128 (2016). “Dissecting jets and missing energy searches using n-body extended simplified models”, JHEP 1608, 038 (2016). J Li, R Patrick, P Sharma and AG Williams, “Boosting the charged Higgs search prospects using jet substructure at the LHC”, JHEP 1611, R Foot and J Gargalionis, “Explaining the 750 GeV diphoton 164 (2016). excess with a colored scalar charged under a new confining gauge interaction”, Phys Rev. D 94(1), 011703 (2016). S Akula, C Balázs and GA White, “Semi-analytic techniques for calculating bubble wall profiles”, Eur. Phys. J. C 76(12), 681 (2016). E Conte, B Fuks, J Guo, J Li and AG Williams, “Investigating light NMSSM pseudoscalar states with boosted ditau tagging”, JHEP 1605, L Wu, B Yang and M Zhang, “Little Higgs dark matter after PandaX- 100 (2016). II/LUX 2016 and LHC Run-1”, JHEP 1612, 152 (2016). S Moretti, R Santos and P Sharma, “Optimising charged Higgs boson A Kobakhidze, C Lagger and A Manning, “Constraining searches at the Large Hadron Collider across bbW ± final states”, noncommutative spacetime from GW150914”, Phys. Rev. D 94(6), Phys. Lett. B 760:697–705 (2016). 064033 (2016). PTP Hutauruk, IC Cloët and AW Thomas, “Flavor dependence of the J Dragos, R Horsley, W Kamleh, DB Leinweber, Y Nakamura, PEL pion and kaon form factors and parton distribution functions”, Phys. Rakow, G Schierholz, RD Young and JM Zanotti, “Nucleon matrix Rev. C 94(3), 035201 (2016). elements using the variational method in lattice QCD”, Phys. Rev. D 94(7), 074505 (2016). S Biswas, EJ Chun and P Sharma, “Di-Higgs signatures from R-parity violating supersymmetry as the origin of neutrino mass”, JHEP 1612, DL Whittenbury, ME Carrillo-Serrano and AW Thomas, “Quark– 062 (2016). meson coupling model based upon the Nambu–Jona Lasinio model”, Phys. Lett. B 762:467–472 (2016). A Scaffidi, K Freese, J Li, C Savage, M White and AG Williams, “Gamma rays from muons from WIMPs: implementation of radiative N Bell, G Busoni, A Kobakhidze, DM Long and MA Schmidt, muon decays for dark matter analyses”, Phys. Rev. D 93(11), 115024 “Unitarisation of EFT amplitudes for dark matter searches at the (2016). LHC”, JHEP 1608, 125 (2016). W Bentz, A Kotzinian, HH Matevosyan, Y Ninomiya, AW Thomas and Q-F Xiang, X-J Bi, P-F Yin and Z-H Yu, “Searching for singlino- K Yazaki, “Quark-jet model for transverse momentum dependent higgsino dark matter in the NMSSM”, Phys. Rev. D 94(5), fragmentation functions”, Phys. Rev. D 94(3), 034004 (2016). 055031 (2016). A Hayreter, X-G He and G Valencia, “CP violation in h → ττ and LFV h → μτ”, Phys. Lett. B 760:175–177 (2016).

49 PUBLICATIONS ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

T Martin, P Skands and S Farrington, “Probing collective effects in P Athron, D Harries, R Nevzorov, AG Williams, “E6 inspired SUSY hadronisation with the extremes of the underlying event”, Eur. Phys. benchmarks, dark matter relic density and a 125 GeV Higgs”, Phys. J. C 76(5), 299 (2016). Lett. B 760:19–25 (2016). ME Carrillo-Serrano, W Bentz, IC Cloët and AW Thomas, “Baryon X-J Bi, Q-F Xiang, P-F Yin and Z-H Yu, “The 750 GeV diphoton excess octet electromagnetic form factors in a confining NJL model”, Phys. at the LHC and dark matter constraints”, Nucl. Phys. B 909:43–64 Lett. B 759:178–183 (2016). (2016). A Fowlie and MH Bardsley, “Superplot: a graphical interface for F Wang, L Wu, JM Yang and M Zhang, “750 GeV diphoton resonance, plotting and analysing MultiNest output”, Eur. Phys. J. Plus 131(11), 125 GeV Higgs and muon g − 2 anomaly in deflected anomaly 391 (2016). mediation SUSY breaking scenarios”, Phys. Lett. B 759:191–199 (2016). XG Wang, C-R Ji, W Melnitchouk, Y Salamu, AW Thomas and P Wang, “Constraints on s − s asymmetry of the proton in chiral JD Clarke and R Foot, “Plasma dark matter direct detection”, JCAP effective theory”, Phys. Lett. B 762:52–56 (2016). 1601(01), 029 (2016). F Staub, P Athron, L Basso, MD Goodsell, D Harries, ME Krauss, A Beniwal, F Rajec, C Savage, P Scott, C Weniger, M White and AG K Nickel, T Opferkuch, L Ubaldi, A Vicente and Alexander Voigt, Williams, “Combined analysis of effective Higgs portal dark matter “Precision tools and models to narrow in on the 750 GeV diphoton models”, Phys. Rev. D 93(11), 115016 (2016). resonance”, Eur. Phys. J. C 76(9), 516 (2016). A Kobakhidze, F Wang, L Wu, JM Yang and M Zhang, “750 GeV ND Barrie, A Kobakhidze and S Liang, “Natural inflation with hidden diphoton resonance in a top and bottom seesaw model”, Phys. Lett. scale invariance”, Phys. Lett. B 756, 390–393 (2016). B 757:92–96 (2016). A Fowlie, C Balázs, G White, L Marzola and M Raidal, “Naturalness of XG Wang, AW Thomas and RD Young, “Electromagnetic contribution the relaxion mechanism”, JHEP 1608, 100 (2016). to charge symmetry violation in parton distributions”, Phys. Lett. B 753:595–599 (2016). R Foot and S Vagnozzi, “Solving the small-scale structure puzzles with dissipative dark matter”, JCAP 1607(07), 013 (2016). N Mehrtens, AK Romer, RC Nichol, CA Collins, M Sahlén, PJ Rooney, JA Mayers, A Bermeo-Hernandez, M Bristow, D Capozzi, ND Barrie, A Kobakhidze, M Talia and L Wu, “750 GeV composite L Christodoulou, J Comparat, M Hilton, B Hoyle, ST Kay, AR Liddle, axion as the LHC diphoton resonance”, Phys. Lett. B 755:343–347 RG Mann, K Masters, CJ Miller, JK Parejko, F Prada, AJ Ross, DP (2016). Schneider JP Stott, A Streblyanska, PTP Viana, M White, H Wilcox JR Stone, PAM Guichon, PG Reinhard and AW Thomas, “Finite nuclei and I Zehavi, “The XMM Cluster Survey: the halo occupation number in the quark-meson coupling model”, Phys. Rev. Lett. 116(9), 092501 of BOSS galaxies in X-ray clusters”, Mon. Not. Roy. Astron. Soc. (2016). 463(2):1929–1943 (2016).

C-W Chiang, X-G He and G Valencia, “Z′ model for b → sℓ l¯ flavor H Li, P Wang, DB Leinweber and AW Thomas, “Spin of the proton in anomalies”, Phys. Rev. D 93(7), 074003 (2016). chiral effective field theory”, Phys. Rev. C 93(4), 045203 (2016). SF King and R Nevzorov, “750 GeV diphoton resonance from singlets J Bellm, S Gieseke, D Grellscheid, S Plätzer, M Rauch, C Reuschle, in an exceptional supersymmetric standard model”, JHEP 1603, 139 P Richardson, P Schichtel, MH Seymour, A Siódmok, A Wilcock, N (2016). Fischer, MA Harrendorf, G Nail, A Papaefstathiou, D Rauch, “Herwig 7.0/Herwig++ 3.0 release note”, Eur. Phys. J. C 76(4), 196 (2016). MJ Dolan, JL Hewett, M Krämer and TG Rizzo, “Simplified models for Higgs physics: singlet scalar and vector-like quark phenomenology”, P Cox, AD Medina, TS Ray and A Spray, “Novel collider and dark JHEP 1607, 039 (2016). matter phenomenology of a top-philic Z′”, JHEP 1606, 110 (2016). JD Vergados, FT Avignone, M Kortelainen, P Pirinen, PC Srivastava, J NF Bell, Y Cai and RK Leane, “Mono-W dark matter signals at the Suhonen and AW Thomas, “Inelastic WIMP-nucleus scattering to the LHC: simplified model analysis”, JCAP 1601(01), 051 (2016). first excited state in125 Te”, J. Phys. G 43(11), 115002 (2016). Z-W Liu, W Kamleh, DB Leinweber, FM Stokes, AW Thomas and TMP Tait and Z-H Yu, “Triplet-quadruplet dark matter”, JHEP 1603, J-J Wu, “Hamiltonian effective field theory study of the N∗(1535) 204 (2016). resonance in lattice QCD”, Phys. Rev. Lett. 116(8), 082004 (2016).

X-F Han, L Wang, L Wu, JM Yang and M Zhang, “Explaining 750 GeV Y Cai and AP Spray, “The galactic center excess from ℤ3 scalar diphoton excess from top/bottom partner cascade decay in two- semi-annihilations”, JHEP 1606, 156 (2016). Higgs-doublet model extension”, Phys. Lett. B 756:309–316 (2016). DL Whittenbury, HH Matevosyan and AW Thomas, “Hybrid stars A Kobakhidze, L Wu and J Yue, “Electroweak baryogenesis with using the quark-meson coupling and proper-time Nambu–Jona- anomalous Higgs couplings”, JHEP 1604, 011 (2016). Lasinio models”, Phys. Rev. C 93(3), 035807 (2016). C Cai, Z-H Yu and H-H Zhang, “750 GeV diphoton resonance as a FP Huang, P-H Gu, P-F Yin, Z-H Yu and X Zhang, “Testing the singlet scalar in an extra dimensional model”, Phys. Rev. D 93(7), electroweak phase transition and electroweak baryogenesis at the 075033 (2016). LHC and a circular electron-positron collider”, Phys. Rev. D 93(10), 103515 (2016). KM Patel and P Sharma, “Interpreting 750 GeV diphoton excess in SU(5) grand unified theory”, Phys. Lett. B 757:282–288 (2016). A Kobakhidze, N Liu, L Wu, JM Yang and M Zhang, “Closing up a light stop window in natural SUSY at LHC”, Phys. Lett. B 755:76–81 (2016).

50 PUBLICATIONS ANNUAL REPORT

A Hayreter, G Valencia, “T-odd correlations from the top-quark A Kobakhidze, A Manning and A Tureanu, “Observable chromoelectric dipole moment in lepton plus jets top-pair events”, Zitterbewegung in curved spacetimes,” Phys. Lett. B 757:84–91 Phys. Rev. D 93(1), 014020 (2016). (2016). P Athron, M Bach, HG Fargnoli, C Gnendiger, R Greifenhagen, J Park, J Li and AG Williams, “Tau reconstruction methods at an electron- S Paßehr, D Stöckinger, H Stöckinger-Kim and A Voigt, “GM2Calc: positron collider in the search for new physics”, Phys. Rev. D 93(7), precise MSSM prediction for (g – 2) of the muon”, Eur. Phys. J. C 075019 (2016). 76(2), 62 (2016). A Ahriche, KL McDonald and S Nasri, “A radiative model for the weak J Barnard, P Cox, T Gherghetta and A Spray, “Long-lived, colour- scale and neutrino mass via dark matter”, JHEP 1602, 038 (2016). triplet scalars from unnaturalness”, JHEP 1603, 003 (2016). F Staub, P Athron, U Ellwanger, R Gröber, M Mühlleitner, P Slavich GA White, “General analytic methods for solving coupled transport and A Voigt, “Higgs mass predictions of public NMSSM spectrum equations: from cosmology to beyond”, Phys. Rev. D 93(4), generators”, Comput. Phys. Commun. 202:113–130 (2016). 043504 (2016). IC Cloët, W Bentz and AW Thomas, “Relativistic and nuclear medium Y Cai and MA Schmidt, “A case study of the sensitivity to LFV effects on the Coulomb sum rule”, Phys. Rev. Lett. 116(3), 032701 operators with precision measurements and the LHC”, JHEP 1602, (2016). 176 (2016). J Li and AW Thomas, “Bottom quark contribution to spin-dependent Y Cai and AP Spray, “Fermionic semi-annihilating dark matter”, JHEP dark matter detection”, Nucl. Phys. B 906:60–76 (2016). 1601, 087 (2016). R Foot, “Dissipative dark matter and the rotation curves of dwarf JD Clarke and RR Volkas, “Technically natural nonsupersymmetric galaxies”, JCAP 1607(07), 011 (2016). model of neutrino masses, baryogenesis, the strong CP problem, and K Hikasa, J Li, L Wu and JM Yang, “Single top squark production as dark matter”, Phys. Rev. D 93(3), 035001 (2016). a probe of natural supersymmetry at the LHC”, Phys. Rev. D 93(3), C Balázs and T Li, “AMS-02 fits dark matter”, JHEP 1605, 033 (2016). 035003 (2016). R Horsley, Y Nakamura, H Perlt, D Pleiter, PEL Rakow, G Schierholz, NL Hall, PG Blunden, W Melnitchouk, AW Thomas and RD Young, A Schiller, R Stokes, H Stüben, RD Young and JM Zanotti, for the “Quark–hadron duality constraints on γZ box corrections to parity- QCDSF and UKQCD collaborations, “QED effects in the pseudoscalar violating elastic scattering”, Phys. Lett. B 753:221–226 (2016). meson sector”, JHEP 1604, 093 (2016). K Huitu, K Rao, SD Rindani and P Sharma, “Effective fermion-Higgs N Liu, L Wu, B Yang and M Zhang, “Single top partner production interactions at an e+e− collider with polarized beams”, Nucl. Phys. B in the Higgs to diphoton channel in the Littlest Higgs Model with 911:274–294 (2016). T-parity”, Phys. Lett. B 753:664–669 (2016). J Cao, C Han, J Ren, L Wu, JM Yang and Y Zhang, “SUSY effects R Horsley, Y Nakamura, H Perlt, D Pleiter, PEL Rakow, G Schierholz, in Higgs productions at high energy e+e− colliders”, Chin. Phys. C A Schiller, R Stokes, H Stüben, RD Young and JM Zanotti, “Isospin 40(11), 113104 (2016). splittings of meson and baryon masses from three-flavor lattice QCD + QED”, J. Phys. G 43(10), 10LT02 (2016). ATLAS collaboration

ATLAS authors from CoEPP are Elisabetta Barberio, Curtis Black, Amelia Brennan, Noel Dawe, Kevin Finelli, Paul Jackson, David Jennens, Takashi Kubota, Brian Le, Lawrence Lee, Tony Limosani, Millie McDonald, Peter McNamara, Marco Milesi, Anthony Morley, Francesco Nuti, Andreas Petridis, Pere Rados, Mark Scarcella, Federico Scutti, Laurence Spiller, Carl Suster, Geoffrey Taylor, Thor Taylor, Francesca Ungaro, Phillip Urquijo, Kevin Varvell, Jin Wang, Martin White, Bruce Yabsley and Daniele Zanzi.

“A measurement of material in the ATLAS tracker using secondary “The laser calibration of the Atlas Tile Calorimeter during the LHC hadronic interactions in 7 TeV pp collisions”, JINST 11(11), P11020 Run 1”, JINST 11(10), T10005 (2016). (2016). “Search for dark matter produced in association with a hadronically – – “Luminosity determination in pp collisions at √s = 8 TeV using the decaying vector boson in pp collisions at √s = 13 TeV with the ATLAS detector at the LHC”, Eur. Phys. J. C 76(12), 653 (2016). ATLAS detector”, Phys. Lett. B 763:251–268 (2016). “Measurement of W+W− production in association with one jet in “Study of hard double-parton scattering in four-jet events in pp – – proton–proton collisions at √s = 8 TeV with the ATLAS detector”, collisions at √s = 7 TeV with the ATLAS experiment”, JHEP 1611, Phys. Lett. B 763:114–133 (2016). 110 (2016).

51 PUBLICATIONS ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

“Search for minimal supersymmetric Standard Model Higgs bosons “The ATLAS data acquisition and high level trigger system”, JINST H/A and for a Z′ boson in the ττ final state produced in pp collisions 11(6), P06008 (2016). at s– = 13 TeV with the ATLAS detector,” Eur. Phys. J. C 76(11), √ “Measurement of the W±Z boson pair-production cross section in 585 (2016). – pp collisions at √s = 13 TeV with the ATLAS detector”, Phys. Lett. B “Dark matter interpretations of ATLAS searches for the electroweak 762:1–22 (2016). production of supersymmetric particles in s– = 8 TeV proton–proton √ “Search for new resonances in events with one lepton and missing collisions”, JHEP 1609, 175 (2016). – transverse momentum in pp collisions at √s = 13 TeV with the “Measurement of the bb¯ dijet cross section in pp collisions at ATLAS detector”, Phys. Lett. B 762:334–352 (2016). s– = 7 TeV with the ATLAS detector”, Eur. Phys. J. C 76(12), √ “Search for top squarks in final states with one isolated lepton, jets, 670 (2016). – and missing transverse momentum in √s = 13 TeV pp collisions with “Search for new phenomena in different-flavour high-mass dilepton the ATLAS detector”, Phys. Rev. D 94(5), 052009 (2016). final states in pp collisions at s– = 13 Tev with the ATLAS detector”, √ “Search for resonances in diphoton events at s– = 13 TeV with the Eur. Phys. J. C 76(10), 541 (2016). √ ATLAS detector”, JHEP 1609, 001 (2016). “Measurement of top quark pair differential cross-sections in the “Measurement of the tt¯ production cross-section using e events dilepton channel in pp collisions at s– = 7 and 8 TeV with ATLAS”, μ √ with b-tagged jets in pp collisions at s– = 13 TeV with the ATLAS Phys. Rev. D 94(9), 092003 (2016). √ detector”, Phys. Lett. B 761:136–157 (2016). “Measurement of the total cross section from elastic scattering in “Measurement of the inelastic proton–proton cross section at pp collisions at s– = 8 TeV with the ATLAS detector”, Phys. Lett. B √ s– = 13 TeV with the ATLAS detector at the LHC”, Phys. Rev. Lett. 761:158–178 (2016). √ 117(18), 182002 (2016). “Search for squarks and gluinos in events with hadronically decaying “Measurements of the Higgs boson production and decay rates tau leptons, jets and missing transverse momentum in proton– and constraints on its couplings from a combined ATLAS and CMS proton collisions at s– = 13 TeV recorded with the ATLAS detector”, √ analysis of the LHC pp collision data at s– = 7 and 8 TeV”, JHEP Eur. Phys. J. C 76, 683 (2016). √ 1608, 045 (2016). “Measurement of exclusive W+W− production and search γγ → “Search for TeV-scale gravity signatures in high-mass final states for exclusive Higgs boson production in pp collisions at s– = 8 TeV √ with leptons and jets with the ATLAS detector at s– = 13 TeV”, Phys. using the ATLAS detector”, Phys. Rev. D 94(3), 032011 (2016). √ Lett. B 760:520–537 (2016). “Search for high-mass new phenomena in the dilepton final state “Search for the Standard Model Higgs boson produced by vector- using proton–proton collisions at s– = 13 TeV with the ATLAS √ boson fusion and decaying to bottom quarks in s– = 8 TeV pp detector”, Phys. Lett. B 761:372–392 (2016). √ collisions with the ATLAS detector”, JHEP 1611, 112 (2016). “Search for Higgs and Z boson decays to ϕγ with the ATLAS “Measurement of the top quark mass in the tt¯ → dilepton channel detector”, Phys. Rev. Lett. 117(11), 111802 (2016). – from √s = 8 TeV ATLAS data”, Phys. Lett. B 761:350–371 (2016). “Measurement of jet activity in top quark events using the eμ final – state with two b-tagged jets in pp collisions at √s = 8 TeV with the “Measurement of the photon identification efficiencies with the ATLAS detector”, JHEP 1609, 074 (2016). ATLAS detector using LHC Run-1 data”, Eur. Phys. J. C 76(12), 666 (2016). “Search for supersymmetry in a final state containing two photons and missing transverse momentum in s –= 13 TeV pp collisions at “Measurement of the double-differential high-mass Drell-Yan cross √ – the LHC using the ATLAS detector”, Eur. Phys. J. C 76(9), 517 (2016). section in pp collisions at √s = 8 TeV with the ATLAS detector”, JHEP 1608, 009 (2016). “Search for bottom squark pair production in proton–proton collisions at s– = 13 TeV with the ATLAS detector”, Eur. Phys. J. C “Charged-particle distributions at low transverse momentum in √ – 76(10), 547 (2016). √s = 13 TeV pp interactions measured with the ATLAS detector at the LHC”, Eur. Phys. J. C 76(9), 502 (2016). “Search for the Higgs boson produced in association with a W boson and decaying to four b-quarks via two spin-zero particles in pp “Measurement of the angular coefficients in Z-boson events using – collisions at 13 TeV with the ATLAS detector”, Eur. Phys. J. C 76(11), electron and muon pairs from data taken at √s = 8 TeV with the 605 (2016). ATLAS detector”, JHEP 1608, 159 (2016). “The performance of the jet trigger for the ATLAS detector during “Search for pair production of gluinos decaying via stop and sbottom 2011 data taking”, Eur. Phys. J. C 76(10), 526 (2016). in events with b-jets and large missing transverse momentum in – pp collisions at √s = 13 TeV with the ATLAS detector”, Phys. Rev. D “Search for heavy long-lived charged R-hadrons with the ATLAS 94(3), 032003 (2016). −1 – detector in 3.2 fb of proton–proton collision data at √s = 13 TeV”, Phys. Lett. B 760:647–665 (2016). “Measurement of the relative width difference of the B0-B̅ 0 system with the ATLAS detector”, JHEP 1606, 081 (2016). “Searches for heavy diboson resonances in pp collisions at s– = 13 TeV with the ATLAS detector”, JHEP 1609, 173 (2016). “Transverse momentum, rapidity, and centrality dependence of √ –—– inclusive charged-particle production in √sNN = 5.02 TeV p + Pb “Search for pair production of Higgs bosons in the bb¯bb¯ final state – collisions measured by the ATLAS experiment”, Phys. Lett. B using proton–proton collisions at √s = 13 TeV with the ATLAS 763:313–336 (2016). detector”, Phys. Rev. D 94(5), 052002 (2016).

52 PUBLICATIONS ANNUAL REPORT

– – “Search for scalar leptoquarks in pp collisions at √s = 13 TeV with “Charged-particle distributions in pp interactions at √s = 8 TeV the ATLAS experiment”, New J. Phys. 18(9), 093016 (2016). measured with the ATLAS detector”, Eur. Phys. J. C 76(7), 403 (2016). “Search for gluinos in events with an isolated lepton, jets and – ± missing transverse momentum at √s = 13 Te V with the ATLAS “Measurements of W Z production cross sections in pp collisions at – detector”, Eur. Phys. J. C 76(10), 565 (2016). √s = 8 TeV with the ATLAS detector and limits on anomalous gauge boson self-couplings”, Phys. Rev. D 93(9), 092004 (2016). “Search for squarks and gluinos in final states with jets and missing – + − transverse momentum at √s = 13 TeV with the ATLAS detector”, Eur. “Measurement of total and differential W W production cross – Phys. J. C 76(7), 392 (2016). sections in proton–proton collisions at √s = 8 TeV with the ATLAS detector and limits on anomalous triple-gauge-boson couplings”, “Measurement of the inclusive isolated prompt photon cross section – JHEP 1609, 029 (2016). in pp collisions at √s = 8 TeV with the ATLAS detector”, JHEP 1608, – 005 (2016). “Search for supersymmetry at √s = 13 TeV in final states with jets and two same-sign leptons or three leptons with the ATLAS “Search for new phenomena in final states with an energetic jet and – detector”, Eur. Phys. J. C 76(5), 259 (2016). large missing transverse momentum in pp collisions at √s = 13 TeV + – using the ATLAS detector”, Phys. Rev. D 94(3), 032005 (2016). “Measurement of event-shape observables in Z → ℓ ℓ events in pp collisions at s– = 7 TeV with the ATLAS detector at the LHC”, “Measurements of the charge asymmetry in top-quark pair √ – Eur. Phys. J. C 76(7), 375 (2016). production in the dilepton final state at√ s = 8 TeV with the ATLAS detector”, Phys. Rev. D 94(3), 032006 (2016). “Search for new phenomena in final states with large jet multiplicities and missing transverse momentum with ATLAS using “Measurements of Z and Z production in pp collisions at γ γγ s– = 13 TeV proton–proton collisions”, Phys. Lett. B 757:334–355 s– = 8 TeV with the ATLAS detector”, Phys. Rev. D 93(11), √ √ (2016). 112002 (2016). “Search for single production of a vector-like quark via a heavy “Study of the rare decays of B 0 and B0 into muon pairs from data s gluon in the 4b final state with the ATLAS detector in pp collisions at collected during the LHC Run 1 with the ATLAS detector”, Eur. Phys. s– = 8 TeV”, Phys. Lett. B 758:249–268 (2016). J. C 76(9), 513 (2016). √ “Search for single production of vector-like quarks decaying into Wb “Search for the Standard Model Higgs boson decaying into bb¯ in pp collisions at s– = 8 TeV with the ATLAS detector”, Eur. Phys. J. produced in association with top quarks decaying hadronically in pp √ – C 76(8), 442 (2016). collisions at √s = 8 TeV with the ATLAS detector”, JHEP 1605, 160 (2016). “Test of CP invariance in vector-boson fusion production of the Higgs boson using the optimal observable method in the ditau decay “Measurement of fiducial differential cross sections of gluon-fusion channel with the ATLAS detector”, Eur. Phys. J. C 76(12), 658 (2016). production of Higgs bosons decaying to WW∗→ eνμν with the – – ATLAS detector at √s = 8 TeV”, JHEP 1608, 104 (2016). “Charged-particle distributions in √s = 13 TeV pp interactions measured with the ATLAS detector at the LHC”, Phys. Lett. B “Search for new phenomena in events with a photon and missing – 758:67–88 (2016). transverse momentum in pp collisions at √s = 13 TeV with the ATLAS detector”, JHEP 1606, 059 (2016). “Measurement of the charged-particle multiplicity inside jets from s– = 8 TeV pp collisions with the ATLAS detector”, Eur. Phys. J. C “Measurement of W± and Z-boson production cross sections in pp √ – 76(6), 322 (2016). collisions at √s = 13 TeV with the ATLAS detector”, Phys. Lett. B 759:601–621 (2016). “A search for top squarks with R-parity-violating decays to all- hadronic final states with the ATLAS detector in s– = 8 TeV proton– “Search for charged Higgs bosons produced in association with √ ± proton collisions”, JHEP 1606, 067 (2016). a top quark and decaying via H → τν using pp collision data – recorded at √s = 13 TeV by the ATLAS detector”, Phys. Lett. B “A search for an excited muon decaying to a muon and two jets in – 759:555–574 (2016). pp collisions at √s = 8 TeV with the ATLAS detector”, New J. Phys. 18(7), 073021 (2016). “Beam-induced and cosmic-ray backgrounds observed in the ATLAS detector during the LHC 2012 proton–proton running period”, JINST “Probing lepton flavour violation via neutrinolessτ ⟶ 3μ decays 11(5), P05013 (2016). with the ATLAS detector”, Eur. Phys. J. C 76(5), 232 (2016).

0 “Search for resonances in the mass distribution of jet pairs “Measurement of the CP-violating phase ϕs and the Bs meson with one or two jets identified as b-jets in proton–proton decay width difference with B 0 → J/ψϕ decays in ATLAS”, JHEP – s collisions at √s = 13 TeV with the ATLAS detector”, Phys. Lett. B 1608, 147 (2016). 759:229–246 (2016). “Measurement of the charge asymmetry in highly boosted top-quark – “Muon reconstruction performance of the ATLAS detector in pair production in √s = 8 TeV pp collision data collected by the – proton–proton collision data at √s = 13 TeV”, Eur. Phys. J. C 76(5), ATLAS experiment”, Phys. Lett. B 756:52–71 (2016). 292 (2016). “Reconstruction of hadronic decay products of tau leptons with the “Identification of high transverse momentum top quarks in pp ATLAS experiment”, Eur. Phys. J. C 76(5), 295 (2016). – collisions at √s = 8 TeV with the ATLAS detector”, JHEP 1606, 093 (2016).

53 PUBLICATIONS ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

“Search for new phenomena with photon+jet events in “Identification of boosted, hadronically decaying W bosons and – – proton–proton collisions at √s = 13 TeV with the ATLAS detector”, comparisons with ATLAS data taken at √s = 8 TeV”, Eur. Phys. J. C JHEP 1603, 041 (2016). 76(3), 154 (2016). “Measurement of the ZZ production cross section in pp collisions at “Performance of pile-up mitigation techniques for jets in pp – – √s = 13 TeV with the ATLAS detector”, Phys. Rev. Lett. 116(10), 101801 collisions at √s = 8 TeV using the ATLAS detector”, Eur. Phys. J. C (2016). 76(11), 581 (2016). “Combination of searches for WW, WZ, and ZZ resonances in “Measurement of the differential cross-section of highly boosted top – – pp collisions at √s = 8 TeV with the ATLAS detector”, Phys. Lett. B quarks as a function of their transverse momentum in √s = 8 TeV 755:285–305 (2016). proton–proton collisions using the ATLAS detector”, Phys. Rev. D ± 93(3), 032009 (2016). “Search for charged Higgs bosons in the H → tb decay channel in – pp collisions at √s = 8 TeV using the ATLAS detector”, JHEP 1603, “Search for anomalous couplings in the Wtb vertex from the 127 (2016). measurement of double differential angular decay rates of single top quarks produced in the t-channel with the ATLAS detector”, JHEP “Measurement of the differential cross-sections of prompt and – 1604, 023 (2016). non-prompt production of J/ψ and ψ(2S) in pp collisions at √s = 7 and 8 TeV with the ATLAS detector”, Eur. Phys. J. C 76(5), 283 (2016). “Measurement of the production cross-section of a single top quark in association with a W boson at 8 TeV with the ATLAS experiment”, “Measurement of D∗±, D± and D± meson production cross sections in – s JHEP 1601, 064 (2016). pp collisions at √s = 7 TeV with the ATLAS detector”, Nucl. Phys. B 907:717–763 (2016). “Search for the production of single vector-like and excited quarks in the Wt final state in pp collisions at s– = 8 TeV with the ATLAS “Search for strong gravity in multijet final states produced in pp √ – detector”, JHEP 1602, 110 (2016). collisions at √s = 13 TeV using the ATLAS detector at the LHC”, JHEP 1603, 026 (2016). “Search for magnetic monopoles and stable particles with high electric charges in 8 TeV pp collisions with the ATLAS detector”, “Measurement of the transverse momentum and ϕ∗ distributions of η – Phys. Rev. D 93(5), 052009 (2016). Drell–Yan lepton pairs in proton–proton collisions at √s = 8 TeV with the ATLAS detector”, Eur. Phys. J. C 76(5), 291 (2016). “Measurements of four-lepton production in pp collisions at s– = 8 TeV with the ATLAS detector”, Phys. Lett. B “Search for new phenomena in dijet mass and angular distributions √ – 753:552–572 (2016). from pp collisions at √s = 13 TeV with the ATLAS detector”, Phys. Lett. B 754:302–322 (2016). “Search for the electroweak production of supersymmetric particles in s– = 8 TeV pp collisions with the ATLAS detector”, Phys. Rev. D “Performance of b-jet identification in the ATLAS experiment”, JINST √ 93(5), 052002 (2016). 11(4), P04008 (2016). “Measurement of jet charge in dijet events from s– = 8 TeV “Measurement of the dependence of transverse energy production √ pp collisions with the ATLAS detector”, Phys. Rev. D 93(5), at large pseudorapidity on the hard-scattering kinematics of – 052003 (2016). proton–proton collisions at √s = 2.76 TeV with ATLAS”, Phys. Lett. B 756:10–28 (2016). “Search for new phenomena in events with at least three photons collected in pp collisions at s– = 8 TeV with the ATLAS detector”, “Search for the Standard Model Higgs boson produced in association √ Eur. Phys. J. C 76(4), 210 (2016). with a vector boson and decaying into a tau pair in pp collisions – at √s = 8 TeV with the ATLAS detector”, Phys. Rev. D 93(9), “Search for direct top squark pair production in final states with two – 092005 (2016). tau leptons in pp collisions at √s = 8 TeV with the ATLAS detector”, Eur. Phys. J. C 76(2), 81 (2016). “Evidence for single top-quark production in the s-channel in – proton–proton collisions at √s = 8 TeV with the ATLAS detector “A new method to distinguish hadronically decaying boosted using the matrix element method”, Phys. Lett. B 756:228–246 (2016). Z bosons from W bosons using the ATLAS detector”, Eur. Phys. J. C – 76(5), 238 (2016). “A search for prompt lepton-jets in pp collisions at √s = 8 TeV with – the ATLAS detector”, JHEP 1602, 062 (2016). “Observation of long-range elliptic azimuthal anisotropies in √s = 13 and 2.76 TeV pp collisions with the ATLAS detector”, Phys. Rev. Lett. “Measurements of top-quark pair differential cross-sections in the – 116(1)7, 172301 (2016). lepton+jets channel in pp collisions at √s = 8 TeV using the ATLAS detector”, Eur. Phys. J. C 76(10), 538 (2016). “Measurement of the charge asymmetry in top-quark pair production in the lepton-plus-jets final state in pp collision data at “Dijet production in s– = 7 TeV pp collisions with large rapidity gaps √ s– = 8 TeV with the ATLAS detector”, Eur. Phys. J. C 76(2), 87 (2016). at the ATLAS experiment”, Phys. Lett. B 754:214–234 (2016). √ “Search for a high-mass Higgs boson decaying to a W boson pair “Measurement of the correlations between the polar angles of in pp collisions at s– = 8 TeV with the ATLAS detector”, JHEP 1601, leptons from top quark decays in the helicity basis at s– = 7 TeV √ √ 032 (2016). using the ATLAS detector”, Phys. Rev. D 93(1), 012002 (2016). “Search for single top-quark production via flavour-changing neutral “Search for dark matter produced in association with a Higgs boson currents at 8 TeV with the ATLAS detector”, Eur. Phys. J. C 76(2), decaying to two bottom quarks in pp collisions at s– = 8 TeV with √ 55 (2016). the ATLAS detector”, Phys. Rev. D 93(7), 072007 (2016).

54 PUBLICATIONS ANNUAL REPORT

“Search for invisible decays of a Higgs boson using vector-boson “Search for an additional, heavy Higgs boson in the H → ZZ decay – – fusion in pp collisions at √s = 8 TeV with the ATLAS detector”, JHEP channel at √s= 8 TeV in pp collision data with the ATLAS detector”, 1601, 172 (2016). Eur. Phys. J. C 76(1), 45 (2016). “Measurements of fiducial cross-sections for tt¯ production with one “Measurements of the Higgs boson production and decay rates and – – or two additional b-jets in pp collisions at √s = 8 TeV using the coupling strengths using pp collision data at √s = 7 and 8 TeV in the ATLAS detector”, Eur. Phys. J. C 76(1), 11 (2016). ATLAS experiment”, Eur. Phys. J. C 76(1), 6 (2016). “Search for flavour-changing neutral current top-quark decays “ATLAS Run 1 searches for direct pair production of third-generation to qZ in pp collision data collected with the ATLAS detector at squarks at the Large Hadron Collider”, Eur. Phys. J. C 75(10), 510 – √s = 8 TeV”, Eur. Phys. J. C 76(1), 12 (2016). (2015); erratum: Eur. Phys. J. C 76(3), 153 (2016). – “Searches for scalar leptoquarks in pp collisions at √s = 8 TeV with “Centrality, rapidity and transverse momentum dependence of the ATLAS detector”, Eur. Phys. J. C 76(1), 5 (2016). isolated prompt photon production in lead–lead collisions at s–—– = 2.76 TeV measured with the ATLAS detector”, Phys. Rev. C “Constraints on non-Standard Model Higgs boson interactions in an √ NN 93(3), 034914 (2016). effective Lagrangian using differential cross sections measured in – the H → γγ decay channel at √s = 8 TeV with the ATLAS detector”, “Study of the spin and parity of the Higgs boson in diboson decays Phys. Lett. B 753:69–85 (2016). with the ATLAS detector”, Eur. Phys. J. C 75(10), 476 (2015); erratum: Eur. Phys. J. C 76(3), 152 (2016). “Measurement of the centrality dependence of the charged-particle pseudorapidity distribution in proton–lead collisions at “Search for massive supersymmetric particles decaying to many jets –—– – √sNN = 5.02 TeV with the ATLAS detector”, Eur. Phys. J. C 76(4), 199 using the ATLAS detector in pp collisions at √s = 8 TeV”, Phys. Rev. (2016). D 91(11), 112016 (2015); erratum: Phys. Rev. D 93(3), 039901 (2016).

+ + + ∗+ “Study of the B c → J/ψD s and B c → J/ψD s decays with the ATLAS “Measurement of the tt¯ production cross-section using eμ events – detector”, Eur. Phys. J. C 76(1), 4 (2016). with b-tagged jets in pp collisions at √s = 7 and 8 TeV with the ATLAS detector”, Eur. Phys. J. C 74(10), 3109 (2014); addendum: Eur. Phys. J. C 76(11), 642 (2016). Belle collaboration

Belle authors from CoEPP are Elisabetta Barberio, Giacomo Caria, Chia-Ling Hsu, Chunhua Li, Luis Pesantez, Martin Sevior, Francesco Tenchini, Phillip Urquijo, Kevin Varvell, Eiasha Waheed and Bruce Yabsley.

+ − “Search for a dark vector gauge boson decaying to π π using “First observation of doubly Cabibbo-suppressed decay of a + − + + − η → π π γ decays”, Phys. Rev. D 94(9), 092006 (2016). charmed baryon: Λ c → pK π ”, Phys. Rev. Lett. 117(1), 011801 0 ∗+ − (2016). “Measurement of the branching ratio of B̅ → D τ ντ relative to 0 ∗+ − 0 0 B̅ → D ℓ νℓ decays with a semileptonic tagging method”, Phys. “First observation of the decay B → ψ(2S)π ”, Phys. Rev. D 93(3), Rev. D 94(7), 072007 (2016). 031101 (2016).

0 + 0 “Study of excited Ξc states decaying into Ξc and Ξ c baryons”, Phys. “Search for the rare decay D → γγ at Belle”, Phys. Rev. D 93(5), Rev. D 94(5), 052011 (2016). 051102 (2016).

0 (∗)0 0 0 0 + − “Measurement of the CKM angle φ1 in B → D¯ h , D¯ →K Sπ π “Inclusive and exclusive measurements of B decays to χc1 and χc2 at decays with time-dependent binned Dalitz plot analysis”, Phys. Rev. Belle”, Phys. Rev. D 93(5), 052016 (2016). D 94(5), 052004 (2016). 0 0 0 “Observation of the decay Bs→ K¯ K¯ ”, Phys. Rev. Lett. 116(16), 161801 “Studies of charmed strange baryons in the ΛD final state at Belle”, (2016). Phys. Rev. D 94(3), 032002 (2016). “Measurement of the decay B → Dℓνℓ in fully reconstructed events 0 + + 0 “Search for a massive invisible particle X in B → e X and and determination of the Cabibbo-Kobayashi-Maskawa matrix + + 0 B → μ X decays”, Phys. Rev. D 94(1), 012003 (2016). element |Vcb|”, Phys. Rev. D 93(3), 032006 (2016). 0 + − “Search for XYZ states in Υ(1S)) inclusive decays”, Phys. Rev. D “Study of B → ρ ρ decays and implications for the CKM angle

93(11), 112013 (2016). ϕ2”, Phys. Rev. D 93(3), 032010; addendum: Phys. Rev. D 94(9), + − 099903 (2016). “First observation of γγ → pp¯K K and search for exotic baryons in pK systems”, Phys. Rev. D 93(11), 112017 (2016). “Measurement of D0– D¯0 mixing and search for CP violation in D0 K+K−, + − decays with the full Belle data set”, Phys. Lett. B “Search for the decay B0 ”, Phys. Rev. D 93(11), 111101 (2016). → π π → ϕγ 753:412–418 (2016). “Observation of Z (10610) and Z (10650) decaying to B mesons”, b b “Search for B0 − + with hadronic tagging at Belle”, Phys. Rev. Phys. Rev. Lett. 116(21), 212001 (2016). → π τ ντ D 93(3), 032007 (2016).

55 PUBLICATIONS ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

0 ∗0 0 + − “First model-independent Dalitz analysis of B → DK , D→K S π π “Measurements of the Υ(10860) and Υ(11020) resonances via + − + − decay”, PTEP 2016(4), 043C01 (2016). σ(e e → Υ(nS)π π )”, Phys. Rev. D 93(1), 011101 (2016). 0 “Study of π pair production in single-tag two-photon collisions”, “Measurement of the lepton forward-backward asymmetry in + − Phys. Rev. D 93(3), 032003 (2016). B → Xsℓ ℓ decays with a sum of exclusive modes”, Phys. Rev. D + − + − 93(3), 032008(2016); addendum: Phys. Rev. D 93(5), 059901 (2016). “Energy scan of the e e → hb(nP)π π (n = 1,2) cross sections and evidence for Υ(11020) decays into charged bottomonium-like states”, Phys. Rev. Lett. 117(14), 142001 (2016). CDF collaboration

CDF author from CoEPP is Antonio Limosani.

“Measurement of the WW and WZ production cross section using “Search for a low-mass neutral Higgs boson with suppressed final states with a charged lepton and heavy-flavor jets in the full couplings to fermions using events with multiphoton final states”, CDF Run II data set”, Phys. Rev. D 94(3), 032008 (2016). Phys. Rev. D 93(11), 112010 (2016). “Measurement of sin2θlept using e+e− pairs from γ∗/Z bosons “Measurement of vector boson plus D∗(2010)+ meson production in eff – produced in pp¯ collisions at a center-of-momentum energy of pp¯ collisions at √s = 1.96 TeV”, Phys. Rev. D 93(5), 052012 (2016). 1.96 TeV”, Phys. Rev. D 93(11), 112016 (2016). “Updated measurement of the single top quark production cross “Measurement of the forward–backward asymmetry of top-quark section and |V | in the missing transverse energy plus jets topology tb – and antiquark pairs using the full CDF Run II data set”, Phys. Rev. D in pp¯ collisions at √s = 1.96 TeV”, Phys. Rev. D 93(3), 032011 (2016). 93(11), 112005 (2016). “Measurement of the inclusive leptonic asymmetry in top-quark “Measurement of the forward–backward asymmetry in low-mass pairs that decay to two charged leptons at CDF”, Phys. Rev. Lett. 113, bottom-quark pairs produced in proton–antiproton collisions”, 042001 (2014); erratum: Phys. Rev. Lett. 117(19), 199901 (2016). Phys. Rev. D 93(11), 112003 (2016). “Measurement of the leptonic asymmetry in tt¯ events produced in ± – “Measurement of the Bc production cross section in pp¯ collisions at pp¯ collisions at √s = 1.96 TeV”, Phys. Rev. D 88(7), 072003 (2013); – √s = 1.96 TeV”, Phys. Rev. D 93(5), 052001 (2016). erratum: Phys. Rev. D 94(9), 099901 (2016). Books

GA White, A pedagogical introduction to electroweak baryogenesis, Morgan & Claypool Publishers, San Rafael, California, 2016.

56 PUBLICATIONS ANNUAL REPORT

Refereed conference proceedings

S Moretti, R Santos and P Sharma, “Charged Higgs boson searches N Fischer and P Skands, “Coherent showers for the LHC”, arXiv at the LHC via multiple bbW± final states”, arXiv 1611.09082 1604.04805 [hep-ph] (2016). [hep-ph] (2016). W Kamleh, JMM Hall, DB Leinweber, BJ Menadue, BJ Owen, AW P Skands and D d’Enterria, “QCD and γγ studies at FCC-ee”, PoS Thomas and RD Young, “The lambda (1405) is a KN molecule”, PoS ICHEP2016 1156, arXiv 1610.06254 [hep-ph] (2016). CD15, 037 (2016). O Oliveira, A Kızılersü, PJ Silva, J-I Skullerud, A Sternbeck and P Athron, M Műhlleitner, R Nevzorov and AG Williams, “Exotic AG Williams, “Lattice landau gauge quark propagator and the Higgs decays in U(1) extensions of the MSSM”, arXiv 1602.04453 quark–gluon vertex”, Acta Phys. Polon. Supp. 9:363–368 (2016). [hep-ph] (2016). P Skands, N Fischer, S Prestel and M Ritzmann, “The VINCIA antenna C Reuschle, J Bellm, S Gieseke, D Grellscheid, S Plätzer, M Rauch, shower for hadron colliders”, arXiv 1609.07205 [hep-ph] (2016). P Richardson, P Schichtel, MH Seymour, A Siódmok, A Wilcock, N Fischer, MA Harrendorf, G Nail, A Papaefstathiou and D Rauch, “NLO MJ Dolan, J Hewett, M Krämer and TG Rizzo, “Simplify your life: efforts in Herwig++”, arXiv 1601.04101 [hep-ph] (2016). towards more model-independent new physics searches”, PoS DIS2016 008 (2016). SD Rindani, P Sharma and A Shivaji, “Unravelling the non-standard top and Higgs couplings in associated top-Higgs production at R Nevzorov and AW Thomas, “E inspired composite Higgs model 6 the high-luminosity LHC”, PoS TOP2015 033, arXiv 1512.07408 and 750 GeV diphoton excess”, EPJ Web Conf. 125, 02021, arXiv [hep-ph] (2016). 1608.00320 [hep-ph] (2016). J-J Wu, T-S Harry Lee, DB Leinweber, AW Thomas and RD Young, A Kobakhidze, L Wu and J Yue, “Electroweak baryogenesis with “Finite-volume Hamiltonian method for scattering in lattice anomalous Higgs couplings”, Int. J. Mod. Phys. Conf. Ser. 43, ππ QCD”, JPS Conf. Proc. 10, 062002 (2016). 1660200 (2016). D Leinweber, W Kamleh, A Kiratidis, Z-W Liu, S Mahbub, D Roberts, OPAL Collaboration (N Fischer et al.), “Measurement of parton F Stokes, AW Thomas and J Wu, “N* spectroscopy from lattice QCD: shower observables with OPAL”, EPJ Web Conf. 120, 05001 (2016). the roper explained”, JPS Conf. Proc. 10, 010011 (2016). AW Thomas, “QCD and a new paradigm for nuclear structure”, EPJ AJ Chambers, R Horsley, Y Nakamura, H Perlt, D Pleiter, PEL Rakow, Web Conf. 123, 01003, arXiv 1606.05956 [nucl-th] (2016). G Schierholz, A Schiller, H Stüben, RD Young and JM Zanotti, H Wang, L Gong, C Li, S Li, H Qu, Z Wang and L Wu, “Overall “Applications of the Feynman-Hellmann theorem in hadron design of magnet girder system for Heps-Tf”, WEPMR047 structure”, PoS LATTICE2015 125 (2016). Proceedings (2016). J Dragos, R Horsley, W Kamleh, DB Leinweber, Y Nakamura, G Valencia, “Colour octet extension of 2HDM”, Int. J. Mod. Phys. A 31, PEL Rakow, G Schierholz, RD Young and JM Zanotti, “Improved 1630033 (2016). determination of hadron matrix elements using the variational method”, PoS LATTICE2015 328 (2016). P Urquijo, “Searching for dark matter at the Stawell Underground Physics Laboratory”, EPJ Web Conf. 123, 04002, arXiv 1605.03299 SD Rindani, P Sharma and AW Thomas, “Polarization of the top [physics.ins-det] (2016). quark as a probe of its chromomagnetic and chromoelectric couplings in single-top production at the Large Hadron Collider”, C Balázs, P Athron, B Farmer and D Kim, “Naturalness, PoS TOP2015 063 (2016). supersymmetry and dark matter”, PoS DSU2015 028 (2016).

57 PUBLICATIONS ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

Conference presentations

Sujeet Akula “Efficient perturbative determination of bubble wall profiles”, Josh Charvetto presenter, CosPA 2016: 13th International Symposium on Cosmology “Vacuum correlation between the electromagnetic and strong and Particle Astrophysics, December 2016. forces”, invited talk, INPC 2016, September 2016.

Peter Athron Sean Crosby “Precision Higgs mass predictions in minimal and non-minimal SUSY “Renewal of Puppet for Australia-ATLAS”, invited talk, 25th Open models”, presenter. Meeting of the Belle II Collaboration, October 2016. Scientific/Organising Committee, SUSY 2016, July 2016. Nadine Fischer Csaba Balázs “Vincia for hadron colliders”, presenter, QCD@LHC 2016, August “GAMBIT: the Global and Modular BSM Inference Tool”, presenter, 2016. DSU 2016 – 12th International Workshop on Dark Side of the Universe, July 2016. Andrew Fowlie “Naturalness and supersymmetry”, invited talk, KITPC Workshop: “Naturalness of the relaxion mechanism: Bayesian naturalness of New Physics at the LHC Run 2, July 2016. next-to-minimal and minimal Supersymmetric Models", presenter, SUSY 2016, July 2016. “GAMBIT”, invited talk, MC4BSM: 10th International Workshop Monte Carlo Tools for Physics Beyond the Standard Model, July 2016. “Naturalness of the relaxion mechanism”, presenter, CosPA 2016: 13th International Symposium on Cosmology and Particle “Dark matter properties implied by Fermi-LAT gamma ray residuals”, Astrophysics, December 2016. presenter, CosPA 2016: 13th International Symposium on Cosmology and Particle Astrophysics, November 2016. “Bayesian approach to naturalness”, presenter, Fine-Tuning, the Multiverse and Life, November 2016. “A brief review of baryogenesis”, plenary, 4th International Workshop on Dark Matter, Dark Energy and Matter-Antimatter Asymmetry, December 2016. Bahman Ghadirian “Radiative neutrino mass generation for a dimension-7 operator and Tommaso Baroncelli its implication for charge lepton flavor violation”, presenter, CosPA 2016: 13th International Symposium on Cosmology and Particle “L3 cooling taskforce report”, report talk, 26th B2GM, October 2016. Astrophysics, November 2016. Ankit Beniwal Dylan Harries “Combined analysis of effective Higgs portal dark matter models”, “Mass spectrum and dark matter in the CSE6SSM”, presenter, SUSY presenter, SUSY 2016, July 2016. 2016, July 2016. Lucien Boland “The 750 GeV diphoton excess: models and precision tools”, presenter, SUSY 2016, July 2016. “Australia-ATLAS tier 2 site update”, HEBiX, Fall 2016, San Fransisco, October 2016. Sophie Hollitt Goncalo Borges “Decay constants and SU (3) symmetry breaking in B-mesons with quenched relativistic”, invited talk, INPC 2016, September 2016. “CEPHFS: a new generation storage platform for Australian high energy physics”, presenter, 22nd International Conference on Paul Jackson Computing on High Energy and Nuclear Physics (CHEP 2016), October 2016. “Recent results from LHC”, invited talk, Symposium 2016 – Interplay between LHC and Flavor Physics, March 2016. Alexander Chambers “The recursive jigsaw reconstruction technique”, poster, ICHEP 2016, “Hadron structure from the Feynman-Hellmann Theorem”, presenter, 38th International Conference on High Energy Physics, August 2016. INPC 2016, September 2016. “Recent ATLAS results on composite dynamics and dark matter”, invited talk, LIO 2016, September 2016.

58 PUBLICATIONS ANNUAL REPORT

Archil Kobakhidze “Welcome on behalf of IUPAP”, presenter, INPC 2016, September 2016. “Heavy axion solution of the strong CP problem”, presenter, PASCOS 2016, July 2016. Marco Milesi Cyril Lagger “Search for the associated production of a Higgs boson with a top quark pair in multilepton final states with the ATLAS detector”, “Constraining noncommutative space-time from GW150914”, presenter, APPC-AIC: Joint 13th Asia Pacific Physics Conference and presenter, CosPA 2016: 13th International Symposium on Cosmology 22nd Australian Institute of Physics Congress Incorporating the and Particle Astrophysics, December 2016. Australian Optical Society Conference, December 2016.

Lawrence Lee Roman Nevzorov “The recursive jigsaw reconstruction technique”, presenter, SUSY “On the smallness of the dark energy density in SUGRA models with 2016, July 2016. Planck scale SUSY breaking and degenerate vacua”, presenter, SUSY 2016, July 2016. Haitao Li “E6 inspired composite Higgs model and 750 GeV diphoton excess”, “TMD Resummation for top quark pair production using SCET”, presenter, SUSY 2016, July 2016. presenter, Effective Field Theories as Discovery Tools, September “The 750 GeV diphoton LHC excesses from singlets in Exceptional 2016. Supersymmetric Standard Model”, presenter, SUSY 2016, July 2016.

Jinmian Li Robert Perry “Investigating light NMSSM pseudoscalar states with boosted ditau “Chiral corrections to electromagnetic form factors in the NJL tagging”, presenter, SUSY 2016, July 2016. model”, invited talk, INPC 2016, September 2016.

Adrian Manning Andreas Petridis “Gravitational waves from low temperature phase transitions”, “Low transverse momentum electrons, presenter, ATLAS Egamma presenter, CosPA 2016: 13th International Symposium on Cosmology Workshop”, November 2016. and Particle Astrophysics, November 2016. Marco Santoni Hrayr Matevosyan “Applications of the recursive jigsaw to searches for SUSY”, “Polarized quark hadronization”, invited talk, International Workshop presenter, SUSY 2016, July 2016. on J-PARC Hadron Physics in 2016, March 2016. “The role of spin in quark hadronization”, invited talk, INPC 2016, Michael Schmidt September 2016. “Sterile neutrino dark matter production from scalar decay”, Zachary Matthews presenter, Dark Side of the Universe DSU Workshop, July 2016. “Unitarisation of EFT amplitudes for dark matter searches at the “Leptonic CP violation and mass hierarchy in the presence of sterile LHC”, presenter, Identification of Dark Matter 2016, July 2016. neutrino”, presenter, SUSY 2016, July 2016. “LHC vs precision experiments – a comparison of the sensitivity to “Leptonic CP violation and mass hierarchy in the presence of sterile LFV D6 operators QQLL”, presenter, SUSY 2016, July 2016. neutrino”, invited talk, INPC 2016, September 2016. “Sterile neutrino dark matter – production from scalar decay”, Bruce McKellar invited talk, NuFact 2016, August 2016. “I — What the International Union of Pure and Applied Physics does Abhishek Sharma for physics and physicists" "II — Electric and magnetic dipole moments, topological phases and “Unravelling the CP phase of top-Higgs coupling in associated Bose-Einstein condensates”, plenary, Siam Physics Congress 2016, production at the LHC”, presenter, SUSY 2016, July 2016. June 2016. Pankaj Sharma “Basic research, open innovation and collaborative economy”, presenter, Fundamental Science and Society, July 2016. “Probing R-parity violation in neutrino-nucleus interactions”, presenter, DAE Symposium, December 2016. “The IUPAP-IUPAC JWG on new elements”, presenter, Annual meeting of IUPAP Commission C-12 on Nuclear Physics, September “Di-Higgs signatures from R-parity violating supersymmetry as the 2016. origin of neutrino mass”, presenter, SUSY 2016, July 2016. “The IUPAP-IUPAC JWG on new elements”, presenter, annual “Charged Higgs search in bosonic-decays using jet substructure at meeting of IUPAP Working Group 9, September 2016. the LHC”, presenter, DAE Symposium, December 2016.

59 PUBLICATIONS ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

Peter Skands Anthony Williams “VINCIA for hadron colliders”, presenter, ICHEP 2016 38th “Combined analysis of effective Higgs portal dark matter model”, International Conference on High Energy Physics, August 2016. plenary, Mass 2016 Conference at CP3-Origins, May 2016. “Stawell Underground Physics Laboratory (SUPL)”, invited talk, AIP Anthony Thomas Congress 2016, December 2016. “QCD, atomic nuclei and neutron stars, plenary”, Humboldt Kolleg on “Combined analysis of effective Higgs portal dark matter model”, Particle Physics, June 2016. presenter, ICHEP 2016 38th International Conference on High Energy “QCD nuclear physics”, plenary, 71st Fujihara seminar, July 2016. Physics, August 2016. “Progress in understanding the nucleon sea”, plenary, International Lei Wu Workshop on Nonperturbaive Phenomena in Hadron and Particle Physics, May 2016. “Monotop/monob signature in Natural SUSY”, presenter, CosPA 2016: 13th International Symposium on Cosmology and Particle “Baryon-baryon interactions at high density”, plenary, International Astrophysics, November 2016. Symposium on Neutron Star Matter, November 2016. “Structure of finite nuclei starting at the quark level”, invited talk, Ross Young INPC 2016, September 2016. “Towards high momentum transfer in lattice QCD”, invited talk, Raymond Volkas Probing Transverse Nucleon Structure at High Momentum Transfer, April 2016. “What I think about when I think about dark matter”, invited talk, “Infrared features of dynamical QED+QCD simulations”, presenter, Beyond the Standard Model in Okinawa 2016, March 2016. Lattice 2016: 34th International Symposium on Lattice Field Theory, “Radiative neutrino mass generation: models, flavour & the LHC”, July 2016. invited talk, PACIFIC Conference 2016, September 2016. “Q-weak and searches of new physics in parity-violating e-p “Outlook for the discovery of new physics”, invited talk, CosPA scattering”, invited talk, Hadronic Contributions to New Physics 2016: 13th International Symposium on Cosmology and Particle Searches (HC2NP), September 2016. Astrophysics, December 2016. “Partonic charge symmetry violation in the nucleon”, presenter, INPC “Radiative neutrino mass generation: models, flavour & the LHC”, 2016, September 2016. invited talk, NCTS Annual Theory Meeting, December 2016. Zhao-Huan Yu Graham White “Triplet-quadruplet fermionic dark matter”, invited talk, East China “Colour breaking baryogenesis – semi-analytical approaches in Particle Physics Meeting, September 2016. particle cosmology”, presenter, SUSY 2016, July 2016. “Color breaking baryogenesis”, invited talk, East China Particle Jason Yue Physics Meeting, September 2016. “Gravitational waves from the phase transition of a nonlinearly “Electroweak baryogenesis in the Z3-invariant NMSSM”, presenter, realised electroweak symmetry”, presenter, Strong and Electroweak CosPA 2016: 13th International Symposium on Cosmology and Matter 2016, July 2016. Particle Astrophysics, December 2016. Daniele Zanzi Martin White “ATLAS trigger performance (Jets, taus and Etmiss)”, plenary talk, “The particle physics of dark matter”, invited talk, Diving into the Atlas Overview Week, June 2016. Dark, July 2016. “The Global and Modular BSM Inference Tool (GAMBIT)”, presenter, SUSY 2016, July 2016.

60 PUBLICATIONS ANNUAL REPORT

CoEPP annual workshop

VAM Radescu (Ruprecht-Karls-Universitaet Heidelberg), “QCD and Presentations parton distribution functions” and “Precision of proton structure for discoveries at LHC”. S Akula, “SUGRA GUTS”. M Schmidt, Neutrino Physics, “Origin of neutrino mass and its P Athron, “Exploring new physics with flexible tools”. experimental test”. C Balázs, “GAMBIT” (the Global and Modular BSM Inference Tool). F Scutti, “Inclusive search for same-sign di-lepton signatures at the E Barberio, “SABRE dark matter search and the SUPL ATLAS experiment”. underground facility”. P Sharma, “Optimising the charged Higgs searches at the LHC in N Bell, “Particle–antiparticle asymmetries”. 2HDM”. G Busoni, “Dark matter”. GN Taylor, “Collider detector design” and “Interaction of particles with matter summary of CoEPP and activities”. Y Cai, “Semi-annihilating dark matter”. F Tenchini, “Belle 2 PID performance and vertexing”. A Clark (University of Geneva), “Comments on ATLAS Run 2” (2015–17). M Trodden (University of Pennsylvania), “Theoretical aspects of cosmic acceleration”. J Clarke, “Self-interacting dark matter direct detection (and implications for Stawell)”. F Ungaro, “Search for third generation squarks with ATLAS Run-II data”. HV Cliff (University of Cambridge), “Cambridge, CoEPP and the LHC”. P Urquijo, “Belle II physics”. T Corbett (Stony Brook), “Effective field theory”. J Wang, “Measurement of the Wt production cross-section at s– = 13 TeV”. N Dawe, “Deep learning jet images”. √ L Wu, “Possible phenomenological explanations of M Dolan (SLAC National Accelerator Laboratory), “Higgs physics”. 750 GeV resonance”. D Dossett, “Calibration and alignment at the Belle II experiment”. Z Yu (University of Melbourne), “The 750 GeV diphoton excess and K Finelli, “ATLAS top quark physics in Run 2”. its possible connection to dark matter”. R Foot, “Dark matter”. A Fowlie, “Fine tuning relaxion models”. Posters PD Jackson, “Experimental anomalies”. N Barrie, “Gravitational wave instabilities in the cosmic neutrino background”. A Kobakhidze, “New solution to the strong CP problem with exotic quarks”. A Beniwal, “Combined analysis of effective Higgs portal dark matter models”. M Kruse (Duke University), “Duke and CoEPP: studies of multilepton final states”. I Bigaran, “Testing simplified dark matter models at the LHC”. L Lee Jr, “Searches for strongly produced supersymmetry in ATLAS T Bloomfield, “Measurement of direct CP violation and branching 0 0 0 Run II”. ratio in B → D π Using Belle Detector”. H Li, “Resummation effects on top quark pair production”. A Brennan, “Simplified models of dark matter at ATLAS”. J Li, “Search for light NMSSM pseudoscalar in neutralino decays with G Caria, “Software improvements for the Belle II SVD”. di-tau tagging”. J Clarke, “Self-interacting dark matter direct detection (and K Mcdonald, “Three-loop models of neutrino mass measure the age implications for Stawell)”. of the Universe to 1%”. P Cox, “Unnatural Composite Higgs at the LHC”. A Morley, “Tracking and minimum-bias analysis in ATLAS Run 2”. R Coy, “Freeze-in of light dark matter”. J Mould (Swinburne University), “Taipan, an AAO/ARC project”. T Dutka, “Neutral naturalness and leptogenesis”. R Nevzorov, “LHC signatures and cosmological implications of the E 6 D Duvnjak, “Remote installation of the SctRodDaq Software”. inspired SUSY models”. J Ellis, “TiKZ-Feynman: a new program for drawing Feynman U Parzefall (University of Freiburg), “The ATLAS strip diagrams in LaTeX”. tracker upgrade”. N Fischer, “Matrix-element corrections in Vincia”. AG Petridis, “Summary of the supersymmetric electroweak searches in Run I and prospects for Run II”. J Gargalionis, “Radiative neutrino mass models at the LHC”.

61 PUBLICATIONS ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

B Ghadirian, “Radiative neutrino mass generation”. M Milesi, “Non prompt lepton background estimation for the ttH → ℓℓ+jets analysis in the ATLAS experiment @LHC”. D Harries, “Sparticle spectrum and dark matter observables in an E6 inspired SUSY model with a 125 GeV Higgs”. F Nuti, “Search for anomalous production of prompt same-sign

0 0 lepton pairs and doubly charged Higgs with 8 TeV data”. A Hawthorne, “Direct CP violation in B →Ksπ at Belle”. D Peukert, “Studying the use of recursive jigsaw variables in the S Hollitt, “B-physics in lattice QCD and at Belle II”. ATLAS Z+Met search for supersymmetry”. C Hsu, “Belle”. C Pyke, “Experiment at SUPL”. A Huitfeldt, “Development of a method to share SCT clusters in the P Rados, “Search for the VH production of the Higgs boson using ATLAS detector track reconstruction”. H → WW* decays with the ATLAS detector”. N Ivancevic, “Towards a regularization that respects spacetime N Rajcic, “Tagging jets and neural nets”. structure”. T Ruggeri, “Background simulations at SUPL”. J Koo, “Cosmic ray telescope for muon flux measurements at SUPL”. M Santoni, “Studies of multi b-jets final states using the recursive C Lagger, “Backreaction of particle production on false vacuum jigsaw reconstruction technique”. decay”. A Scaffidi, “Implementation of radiative muon decays for dark B Le, "Measuring Higgs properties with H →ττ decays at – matter analyses”. √s = 13 TeV with ATLAS". M Schroor, “Dark QCD”. R Leane, “Indirect detection of a complete dark sector”. C Suster, “Beam spot studies in ATLAS Run 2”. A Lifson, “Maximally helicity violating amplitudes”. M Talia, “The effective MSSM”. S Lonsdale, “Origin of matter and dark matter from a broken mirror symmetry”. T Taylor, “Same-sign WW scattering analysis”. C MacQueen, “Shedding light on dark matter: the search for a dark E Waheed, “Right handed currents and other new physics in photon in radiative processes at Belle”. semileptonic B decays”. I Mahmood, “Experiment at SUPL”. D Wakeham, “Higgs inflation”. A Manning, “Fermions in non-inertial frames”. J Webb, “Belle II SVD measurements”. M McDonald, “Determination of the tau energy scale uncertainty G White, “Colour breaking baryogenesis”. using single particle response measurements for Run II”. S Williams, “Belle II SVD construction”. P McNamara, “The ATLAS tau FTK trigger”. J Yue, “Baryogenesis with electroweak symmetry realised non-linearly”.

62 PUBLICATIONS ANNUAL REPORT

63 PUBLICATIONS PERFORMANCE ANNUAL REPORT

Prizes and awards

Wessam Badr Daniel Murnane ND Goldsworthy Scholarship for Physics (MSc and PhD) Award, “3 Minutes Thesis” Award, Faculty of Science, University of Adelaide University of Melbourne Joni Pham Nicole Bell The Klein Prize in Experimental Physics Award, University Fellow of the American Physical Society of Melbourne

Joshua Ellis Harry Poulter ND Goldsworthy Scholarship for Physics (MSc and PhD) Award, CoEPP Scholarship University of Melbourne Shi Qiu John Gargalionis CoEPP Scholarship The Professor Kernot Research Scholarship in Physics Award, University of Melbourne Isaac Sanderson Paul Jackson ND Goldsworthy Scholarship for Physics (MSc and PhD) Award, University of Melbourne Distinguished Award for Sustained Research, University of Adelaide Marco Santoni Stephen Keyte Runner-up: CoEPP Workshop Poster Competition ND Goldsworthy Scholarship for Physics (MSc and PhD) Award, University of Melbourne

Brian Le Winner: CoEPP Workshop Poster Competition

Rebecca Leane The Betty Laby ECR Travel Bursary Award, University of Melbourne Young Scientist Research Prize, Royal Society of Victoria

Ruihao Li CoEPP Scholarship

Shelley Liang Runner-up: CoEPP Workshop Poster Competition

Millie McDonald John Tyndall Scholarship, University of Melbourne

Bruce McKellar T.D. Lee Prize of “The Universe”: The 1993 discovery of the He- McKellar-Wilkens (HMW) Phase, “The Universe” ACosPA Org Associate Professor Nicole Bell was named a Fellow of the American Physical Society (APS) “For fundamental contributions regarding the interface of astrophysics and particle physics, particularly in neutrino astrophysics and cosmology, and dark matter phenomenology.”

65 PERFORMANCE ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

Phiala Shanahan Geoffrey Taylor Winner 2016 Bragg Gold Medal, Australian Institute of Physics Redmond Barry Distinguished Professor, University of Melbourne Science Excellence Awards in South Australia – PhD Research Excellence, South Australia Department of State Development Ray Volkas 2016 Postgraduate Alumni University Medalist, University of Adelaide 2016 Harrie Massey Medal and Prize, Institute of Physics/Australian Institute of Physics 2017 Dissertation Award of the Topical Group on Hadron Physics, American Physical Society David Wakeham Justin Tan ND Goldsworthy Scholarship for Physics (MSc and PhD) Award, University of Melbourne The Jean E Laby Bursary Award, University of Melbourne CoEPP Scholarship Media report

In 2016, CoEPP received a total of 298 media “hits” (print and online) with a potential viewership of 28,073,741 (data sourced through Meltwater).

Stories appeared in national and international outlets, and via dark matter” (Lisa Clausen, SBS online), and “Hunt for dark matter syndicated press. Coverage included stories about SUPL, Photowalk sends scientists underground in a Victorian goldmine” (Bridie Smith, exhibition, CoEPP involvement in the Collider exhibition at the The Age). CoEPP generated a total of 11 media releases/news items Powerhouse Museum, and new partnerships forged with Fermilab over the year. in the United States and IHEP in China. CoEPP worked closely with journalists on a number of feature articles, including “Digging for

PhD student Rebecca Leane was awarded the Royal Society of Victoria Young Scientist Research Prize for the Physical Sciences.

66 PERFORMANCE ANNUAL REPORT

Centre-recognised leadership

Boards and official roles Archil Kobakhidze Co-chair, CosPA 2016 Csaba Balázs Bruce McKellar AC International Advisory Board member, Dark Side of the Universe International Workshop series President, International Union of Pure and Applied Physics Editorial Board member, Scientific Reports (Nature Publishing) Martin Sevior Particle Phenomenology Group Leader, Monash University Belle and Belle II Executive Board member Convener of Core Development, GAMBIT collaboration Member, International Advisory Committee, Europe–Asia–Pacific Co-chair, SUSY 2016 Conference Summer School Dark Matter Working Group leader, Australian CTA contingent Hadronic B-Decays group co-convener – Belle

Elisabetta Barberio Peter Skands University of Melbourne ATLAS Team Leader International Advisory Board member, MPI@LHC workshop series Member, Publication Committee of ATLAS International Advisory Board member, CERN-Fermilab Hadron- ATLAS Fast Track Trigger Institution Board member Collider Physics Summer School Spokesperson, SABRE South International Advisory Board member, Monte Carlo Tools for Beyond the Standard Model Physics (MC4BSM) workshop series Institutional Board Chair, SABRE South Member, conference committee, Workshop on High-Precision Alpha Nicole Bell S measurements: from LHC to FCC-ee Leader, VINCIA collaboration Editorial Board member, Scientific Reports (Nature Publishing) Co-chair, pre-SUSY summer school 2016 Geoffrey Taylor International Advisory Committee, CosPA 2016 conference ATLAS National Contact Physicist (Australia) International Advisory Committee, International Neutrino Summer Vice-Chair and Chair-designate, Asian Committee for Future School 2016 Accelerators General Assembly member, Asia–Pacific Organization for Cosmology Member, AsiaHEP Asia–Pacific High Energy Physics Panel and Particle Astrophysics Member, International Advisory Committee CEPC (China) Caroline Hamilton Australian Representative, ATLAS and WLCG Resource Review boards Digital Governance Committee member, Interactions Collaboration Member, Melbourne Grammar School Council Board member, Interactions Collaboration Member, Melbourne Grammar School Foundation Board Paul Jackson Member, International Advisory Committee, LCWS2016 University of Adelaide ATLAS Team Leader Member, International Advisory Committee, Lepton Photon 2017 ATLAS Collaboration Board member Member, International Advisory Committee, International Conference Chair, Advisory Board, ATLAS Collaboration Board on High Energy Physics ATLAS ITK Institute Board member Member, International Advisory Committee, Rencontres de Vietnam 2016 ATLAS SCT Institute Board member Chair, (NSS) IEEE NSS-MIC, Sydney 2018 International Particle Physics Outreach Group National Contact Physicist Invited Australian member, Funding Agencies for Large Colliders Belle II Institute Board member Member, International Advisory Committee, International Conference on High Energy Physics Theory to Experiment

67 PERFORMANCE ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

Anthony Thomas Martin White Past-Chair, International Union of Pure and Applied Physics Working Co-leader of GAMBIT collaboration Group on International Cooperation in Nuclear Physics Member, local organising committee, SUSY 2016 Vice-Chair, Asian Nuclear Physics Association Session chair at “(Re) interpreting the results of new physics Editorial Board member, Journal of Physics G searches at the LHC” (CERN, Geneva) Editorial Board member, Progress in Particle and Nuclear Physics Co-organiser of international workshop on statistical inference for particle astrophysics (Oban, Scotland) Chair, International Conference on Nuclear Physics 2016 Chair, Program Committee, International Conference on Nuclear Anthony Williams Physics 2016 SABRE Institutional Board Representative Member, local organising committee, International Conference on Nuclear Physics 2016 Member, SUPL Project Steering Committee Member, International Organising Committee, IHEP-T2E 2017, Malaysia Member, International Advisory Committee, 9th Workshop on Hadron Physics in China and Opportunities Worldwide Member, local organising committee, International Conference on Nuclear Physics 2016 Member, International Advisory Committee, Asia Pacific Few Body Conference 2017 Bruce Yabsley Member, International Advisory Committee, Baryons 2016 Member, International Advisory Committee, International Workshop Member, International Advisory Committee, Hadron 2017 on Charm Physics Member, International Advisory Committee, NSTAR 2017 Member, ATLAS Speakers Committee

Phillip Urquijo ATLAS and LHC working groups, Physics Coordinator, Belle II Higgs analysis groups Belle and Belle II Executive Board member Belle II Institution Board member Elisabetta Barberio CKM convener, Belle Institute Board representative, FTK Subconvenor, Higgs to tau tau Kevin Varvell University of Sydney ATLAS Team Leader Amelia Brennan Belle and Belle II Institute Board member LHC Dark Matter Forum Member, local organising committee, SUSY 2016 Kevin Finelli Member, local Organising committee, CosPA 2016 Top working group, single-top quark subgroup convener Raymond Volkas t W analysis contact Vice-President, Asia–Pacific Organization for Cosmology and Particle ATLAS contact for common fiducial acceptance on LHCTOPWG Astrophysics ATLAS Top cross-section subgroup convenor Member, Executive Committee, Division of Astrophysics, Cosmology and Gravitation, Association of Asia–Pacific Physical Societies Paul Jackson Member, International Advisory Committee for the International Supersymmetry squark/gluino search leader Conference on Neutrino Physics and Astrophysics Convenor, ATLAS supersymmetry recursive jigsaw analysis Commission 11 (C-11) member, International Union of Pure and Applied Physics Takashi Kubota Divisional Associate Editor (Particles and Fields), Physical Subconvenor and editor, VH, H WW Review Letters → Co-chair, SUSY 2016 Lawrence Lee ATLAS Supersymmetry 0-lepton search analysis contact

68 PERFORMANCE ANNUAL REPORT

Antonio Limosani Abhishek Sharma Editor and coordinator, AIDA ATLAS low pT e/gamma tag and probe

Chair, ATLAS Software Performance Management Board Phillip Urquijo Responsible for external packages in the ATLAS Software Infrastructure team Editor, New Phenomena Producing Trilepton Resonances FTK working group member Anthony Morley Tau trigger working group member Convenor, ATLAS Beamspot Group Convener and editor, ATLAS minimum bias 13 TeV Jin Wang Editorial Board Chair, reconstruction of hadronic decay products of HGam PMG contact tau leptons with the ATLAS experiment Martin White Brian Petersen Chair, editorial board for ATLAS paper on general gauge mediation Supersymmetric partners to quarks and gluons Editorial board member, ATLAS dilepton stop searches

Andreas Petridis Bruce Yabsley Working group convenor, ATLAS Supersymmetry EWK ππΥ analysis contact ATLAS 2/3 lepton supersymmetry search analysis contact ATLAS Subgroup convenor, onia production and b ATLAS low pT e/gamma tag and probe cross-section measurements

Federico Scutti Daniele Zanzi Contact and editor, same-sign di-lepton analysis within the ATLAS Sub-convenor, CP for Higgs to tautau EXOTICS working group Convener, tau trigger slice Editor and analyser, tau trigger efficiency measurement notes Member, Higgs working group coordination

69 PERFORMANCE ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

Key performance indicators

KPI Target 2016 Actual 2016 Number of research outputs – journal publications 80 219a Number of research outputs – refereed conference proceedings 35 23

Quality of research outputs 50% 96% Citation data for publications 1,000 5,991 Number of invited talks/papers/keynote lectures at major international 40 23 meetings

Number and nature of commentaries about the Centre’s achievements – 6 11 media releases

Number and nature of commentaries about the Centre’s achievements – 4 298 articles (including television and radio)

Number of attended professional training courses for staff and 15 21 postgraduate students

Number of Centre attendees at all professional training courses 20 33 Number of new postgraduate students working on core Centre research and 12 12 supervised by Centre staff – PhD

Number of new postgraduate students working on core Centre research and 8 11 supervised by Centre staff – Masters by Research and Masters by Coursework

New postdoctoral researchers working on core Centre research 2 0 New Honours students working on core Centre research and supervised by 12 5 Centre staff

Number of postgraduate completions and completion times by students 14 16 working on core Centre research and supervised by Centre staff

Number early career researchers (within 5 years of completing PhD) working 16 25 on core Centre research

Number of students mentored 60 97 Number of mentoring programs 7 7 Number international visitors and visiting Fellows 15 42 Number of national/international workshops held/organised by the Centre 3 4b

Number of visits to overseas laboratories and facilities 35 81 Number of government/industry and business community briefings 5 6 a 125 ATLAS, 24 Belle II, 10 CDF, 94 theory and other. Activities with Belle and CDF are listed in the annual report but are not included in KPI reporting. b Includes SUSY 2016, INPC, CosPA. CoEPP centre workshop.

70 PERFORMANCE ANNUAL REPORT

Number and nature of public awareness programs

KPI Target 2016 Actual 2016 School visits 20 13 National Science Week event participation 5 3 Other public activities 6 4

Currency of information on the Centre’s website

KPI Target 2016 Actual 2016 Number of website hits 20,000 43,429 Public talks given by Centre staff 20 12 Prizes and awards 16 29

Number of new organisations collaborating with or involved in the Centre 2 2

Examples of relevant interdisciplinary research supported by the Centre

KPI Target 2016 Actual 2016 FCC research studya 1 1 a CoEPP is participating with CERN and the Australian Synchroton through a formal Memorandum of Understanding in accelerator science on a study of some specific aspects of a Future Circular Collider (FCC). This study will investigate aspects on the long term goal of a hadron collider with a centre-of-mass energy of the order of 100TeV in a new tunnel of 80–100 km circumference. The study also includes a lepton collider and its detectors as a potential intermediate step.

71 PERFORMANCE ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

Financial statements

Statement of income and expenditure for the year ended 31 December 2016

2011 reporting 2012 reporting 2013 reporting 2014 reporting period period period period Carry forward $0 $3,738,983 $3,940,654a $4,403,387b Income ARC indexed income $3,656,701 $3,797,390 $3,943,493 $4,062,667 Node contribution $1,632,000 $752,000 $1,151,785c $1,238,678c

NeCTAR $484,785 $161,595 $64,638

Other $1,055 $17,333 $201,904d $1,880

Total income $5,289,756 $5,051,508 $5,458,777 $5,367,863 Balance $5,289,756 $8,790,491 $9,399,431 $9,771,250 Expenditure Salaries $1,132,439 $2,989,585 $3,951,676 $3,468,297 Equipment $28,365 $186,544 $61,687 $161,739

Maintenance $265,379 $80,923 $582,041e

Travel, accomodation $260,725 $559,307 $610,838 $666,854 and conferences Scholarships $57,370 $35,482 $49,309

Services and general $129,244 $497,999 $155,907 $99,555

Outreach and mediah $49,886 $60,774 NeCTAR $293,622 $428,462 $153,522 New initiatives

Total expenditure $1,550,773 $4,849,806 $5,374,861 $5,242,091 Balance $3,738,983 $3,940,685 $4,024,570 $4,529,160

Table continues on opposite page

72 PERFORMANCE ANNUAL REPORT

2017 reporting 2018 to end 2015 reporting 2016 reporting period of centre period period (estimated) (estimated) Carry forward $4,529,160 $4,412,131 $3,310,641 $2,634,073 Income ARC indexed income $4,135,430 $4,205,732 $4,268,819 $0 Node contribution $1,195,368 $1,195,640 $1,192,000 $0 NeCTAR $0 $0 $0 $0 Other $18,182 $2,500 $5,000 $2,500 Total income $5,348,980 $5,403,872 $5,465,819 $2,500 Balance $9,878,140 $9,816,003 $8,776,460 $2,636,573 Expenditure Salaries $4,118,841 $4,378,042 $4,037,179 $1,947,373

Equipment $40,999 $143,171 $261,912 $0 Maintenance $225,788f $755,335f $426,095 $295,923 Travel, accomodation $648,111 $886,871 $878,201 $348,278 and conferences

Scholarships $150,717g $140,626g $135,000 $45,000 Services and general $186,010 $96,578 $148,000 $0 Outreach and mediah $89,614 $56,643 $106,000 $0 NeCTAR $5,929 $32 $0 $0 New initiatives $48,063 $150,000 $0 Total expenditure $5,466,009 $6,505,362 $6,142,387 $2,636,573i Balance $4,412,131 $3,310,641 $2,634,073 $0

73 PERFORMANCE ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

Financial summary

Notes to the statement of income ARC funding and expenditure The Centre for Excellence for Particle Physics at the Terascale is funded by the Australian Government through the Australian a Carry forward adjustments from 2012. Research Council. The funding for the Centre is for seven years with b Adjustment to Adelaide opening balances, due to timing an annual base contribution to the Centre of $3,600,000. Additional differences in income transfer between University of Melbourne amounts each year for indexation increase this funding. and University of Adelaide and carry forward adjustments to In 2016 the Centre received $4,205,732 of indexed ARC funds. Melbourne and Sydney. This was distributed to the four nodes of the Centre according to c Monash School of Physics Contribution for 2013 was paid in Q1 the Centre’s inter-institutional agreement and was used to fund 2014 and is reported in 2014 Annual Report. operational expenses. d “Other” comprises adjustments relating to prior year income adjustments, corrections to NeCTAR carry forward, and income Institutional funding timing differences. Under the Centre’s funding agreement with the ARC the e Includes total expense for ATLAS M&O of $302,217, with collaborating institutions are required to contribute the following $140,685 relating to 2013 expense. annual amounts: f No payment made for ATLAS M&O in 2015. Additional payment made in 2016. The University of Melbourne $660,000 g Scholarship amount includes additional expense for student The University of Sydney $235,000 support and summer studentships. Monash University $132,000 h Outreach and Media was included under Services and General in 2011 and 2012. The University of Adelaide $165,000 i Expenditure estimates have been allocated between salaries, scholarships, travel and maintenance as the Centre winds up Payments for 2016 from the institution were: operation. The University of Melbourne $660,000 ARC contract The University of Sydney $235,000

The Centre for Excellence for Particle Physics at the Terascale Monash University $135,640 commenced as a Centre of Excellence on 1 January 2011. Funding The University of Adelaide $165,000 was approved for seven years ending in December 2017, with a review held in 2014. Additional funding and in-kind support from the four collaborating institutions and in-kind support from the seven partner institutions provide further funding and support for the Centre.

74 PERFORMANCE ANNUAL REPORT

Other $2,500 2016 income Total income $5,401,372

Node contribution $1,195,640

ARC indexed income $4,205,732

Services and general NeCTAR $96,578 $32 2016 Scholarships New initiatives expenditure $140,626 $48,063 Equipment Outreach and media Total expenditure $143,171 $56,643 $6,505,362 Maintenance $755,335

Travel, accomodation and conferences $886,871

Salaries $4,378,042

75 PERFORMANCE ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

In-kind contributions Notes on in-kind contributions Decrease in Research Computing in-kind in 2016 due to change in 2016 costing model, without changes to service levels. reporting CERN provides considerable in-kind support to CoEPP’s research Contributor period activities predominantly through access to the LHC. University of Melbourne $2,556,413 University of Melbourne – Research $43,200 Computing University of Adelaide $601,960 University of Adelaide – Research $3,000 Computing University of Sydney $515,548 University of Sydney – Research Computing $3,000 Monash University $143,106 University of Pennsylvania $11,227 Cambridge University $11,227 L’Universite de Geneve $11,227 Albert Ludwigs Universität Freiburg $33,680 INFN Sezione di Milano $22,454 Duke University $11,227 University of Minnesota $22,856 University of Melbourne shared General $19,000 Purpose GPU University of Melbourne – Cloud computer $361,788

Total $4,370,913

In-kind Cloud General computer purpose CPU contributions University of Melbourne Total contribution $4,370,913 Research University of computing Adelaide

University of Sydney

Monash University

International universities

0 $1,000,000 $2,000,000 $3,000,000

76 PERFORMANCE ANNUAL REPORT

77 PERFORMANCE LOOKING AHEAD ANNUAL REPORT

Activity plan

Higgs program The research program on the radiative generation of neutrino mass will continue to be pursued vigorously during 2017, involving In 2017, CoEPP researchers will analyse the new data from Run 2 for researchers at all four nodes. Specific lines of investigation will important and challenging Higgs boson property measurements. include the study of the connections between radiative neutrino Twice as much data is now available from the runs in 2016 than mass generation and some anomalies in flavour physics experiments expected; this means that analysis studies can proceed deeper that hint at the violation of lepton flavour universality (Melbourne into the rarer decay channels. These include the observation of and Monash). Exotic particles such as scalar leptoquarks are central the H → 휏휏 decay, the measurement of the CP quantum number to both topics, and thus suggest a possible connection. This work of the Higgs boson coupling to fermions, the search for the Higgs will benefit from Australian involvement in the Belle II experiment, boson production in association with a pair of top quarks and the which will take data from 2018 onwards and will help resolve these measurement of the VH (→WW) cross-section. anomalies, possibly by confirming the existence of new physics. The use of effective operators that violate lepton number by two units Higgs physics theory has formed the basis of a significant fraction of the CoEPP research on neutrino mass generation. In 2017, this approach will be extended With new data at 13 TeV becoming available, CoEPP theorists will to operators that also contain standard model gauge fields, an further explore properties of the 125 GeV Higgs boson and focus area that has been neglected until now (Adelaide, Melbourne and on data analysis within the effective field theory approach to the Sydney). Finally, researchers at the Adelaide, Melbourne and Sydney SM. Theorists will aim to pin down evidence for new physics in nodes plan to collaborate on a major review article on radiative measurements of various couplings, such as Higgs–gauge boson neutrino mass generation during 2017. coupling and Higgs–top quark coupling. New strategies for precision measurements of the Higgs couplings in current and future Precision tests experiments will also be investigated. Efforts to test the predictions of the Standard Model at the highest The new Higgs data will allow testing of various BSM scenarios, such levels of precision will continue using ATLAS data collected in Run 2 as multi-Higgs models, supersymmetric theories and other theories. of the LHC. CoEPP researchers have established leadership in the Model building will also be an active research area. analysis of the top quark, soft QCD signatures, and electroweak CoEPP theorists will investigate cosmological implications of the physics in the ATLAS experiment, and will continue to develop Higgs boson. Research activities will include the electroweak phase new and innovative techniques to fully exploit Run 2 data within transition and baryogenesis, and the Higgs vacuum stability. these areas. The analysis of final states with a single top quark in association with a W boson will be extended to test predictions of Further studies of theoretical ideas, such as SUSY, scale invariance perturbative QCD in new ways. Additionally, an inclusive analysis and cosmological relaxation, motivated by the naturalness principle to study signatures with a two-lepton final state will be developed, will also be a focus. which combines the experience of researchers working on several types of SM measurements to create a unique analysis that is Neutrino mass more inclusive than traditional cross-section measurements. Such CoEPP researchers will expand their study of neutrino mass models studies provide another way to look for new physics beyond the SM and mechanisms, with an emphasis on approaches that can be by testing SM predictions at the most extreme limits available to tested in experiments operating at both the energy and precision experimentalists today. frontiers. New particles predicted in neutrino mass models, Full results from the Q-weak experiment at Jefferson Lab, Virginia particularly radiative models, can give distinctive signatures at the (United States), will be reported in 2016. This is the first dedicated LHC, and CoEPP members will continue their studies of promising measurement to determine the electroweak charge of the proton, variants of such frameworks. Precision tests of neutrino mass models with a precision that can probe new physics in the multi-TeV range. will be explored, including lepton flavour violating processes, in The final results will be based on the full dataset, following the addition to general studies of effective operators that can play a preliminary result published in 2013, which analysed just the first 4% role in neutrino mass generation. These tests will provide further of data taken. information about the underlying mechanism of neutrino mass, and in some cases allow general statements to be made about the Dark matter viability of groups of models. Dark matter research in 2017 will continue to concentrate on model CoEPP researchers will also study connections between the neutrino building, phenomenology and collider detection. CoEPP theorists mass problem and other known shortcomings of the SM. This will develop Beyond the Standard Model theories that incorporate research will include an exploration of relationships between the complete dark matter sectors. Theoretical work on the formulation origin of neutrino mass and the nature of dark matter – CoEPP and validity of dark matter effective field theories will also scientists will expand previous ideas and take them in new be performed. directions. This research will extend the scope of experimental explorations of neutrino mass models, enlarging the spectrum of Experimental studies of LHC dark matter signals will continue, with relevant experiments from the LHC and precision experiments to key CoEPP participation in the ATLAS mono-X working groups. These include dark matter searches (in particular, direct- and indirect- experimental results will be used to constrain effective field theories detection experiments). and simplified models. Complementary constraints on dark matter

79 LOOKING AHEAD ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

models will also be formulated using indirect detection techniques. Research computing In particular, models that can account for the Galactic centre gamma ray excess via the annihilation of various dark matter particles will be In 2017, the Research Computing team will continue to focus on examined. providing excellence in resource reliability and availability. It is also expected that greater engagement with researchers will enhance the The GAMBIT collaboration will continue to perform statistical fits to services the team provides and increase their effective use. collider and astrophysical dark matter information; code and results are planned for release within the year. Continued innovation is a must in the research computing field. As the world moves towards software-as-a-service computing models, During 2016, significant development has occurred for the design and and technology allows a paradigm shift towards infrastructure as construction of the Stawell Underground Physics Laboratory (SUPL) code, the nature of system administration and provision of computing and the dark matter detector, which will be located in the laboratory services will evolve tremendously. The Research Computing team will (Sodium-iodide with Active Background REjection – SABRE). The concertedly drive CoEPP’s computing services towards the emerging laboratory and the experiment have been fully designed; during 2017, technologies and approaches that are delivering the disruptive power it is intended that the laboratory and fitout will be completed, to of new enterprises in the commercial sector. In addition to work enable the SABRE experiment to be in place for 2018. within CoEPP, the Research Computing team will continue to provide support to the BORG project for the Astro group at the University of Supersymmetry Melbourne. It will also provide Ceph Cluster expertise for the University Results will be published for the most exhaustive statistical inference Research Services Team. of the plausibility, naturalness, and discovery prospects of the seven-parameter Minimal Supersymmetric Standard Model. A similar Management and governance outcome for more constrained versions of the model is planned to The IAC will continue its support of the Centre. At the meeting of the follow. This work will be done by the GAMBIT Collaboration, which IAC in Chicago in August 2016, the committee noted that, although the consists of 28 physicists from about 20 international institutes, Centre was unsuccessful in its bid for a new Centre, they continued to including CoEPP members from Adelaide and Monash. In the context have confidence in the Centre’s ability to build on the strengths already of the Next-to-Minimal Supersymmetric Standard Model, CoEPP in place and its capability to carry out the very significant plans clearly researchers will publish their results demonstrating that plausibility of stated in the proposal. electroweak baryogenesis and thermal freeze out of dark matter can account for all the observed matter content of the universe. Personnel CoEPP theorists will scrutinise the exceptional supersymmetric Each year, CoEPP has steadily increased its intake of research Standard Model (E6SSM) further, with more detailed studies of Higgs physics, the implications of dark matter abundance measurements and higher-degree students. Increases across all nodes will be seen in new findings from direct-detection dark matter experiments. Diphoton 2017, particularly within the new research groups in Adelaide and signatures will be examined in this context because E6-inspired Sydney (experimental and theory, respectively). This will bring new models are one of the leading possibilities to explain any potential challenges in future years because Centre funding will cease from the diphoton excess. CoEPP experimental researchers have pioneered new current round in 2018. Nevertheless, the Centre is looking to the future. techniques to perform searches for physics beyond the SM, involving As a priority, all Centre researchers are seeking additional funding the development of new kinematic variables for particles that decay sources to continue, in part, some of the current Centre activities. semi-invisibly. An analysis in the flagship “jets plus missing energy” Some of these funding options are student scholarships and travel discovery channel is in the final stages of completion on the Run 2 funds through their respective universities, industry support, and ATLAS dataset, and will be updated with new data in 2016. This has potential government funding for activities. The Centre is grateful for expanded the discovery reach for supersymmetric squark and gluino ongoing institutional support, in various forms, from collaborating production. Other analyses are targeting final states with two or more organisations. leptons, and various final states with combinations of leptons and b jets. Taken together, these analyses probe gluino and weak gaugino Education and development production, plus all three generations of squarks. Education and development activities will continue to feature strongly across CoEPP in 2017. The graduate summer school will be run for Exotic mesons a fourth year and again held as the lead-in to the annual scientific Further progress in exotic meson studies at the LHC will depend on workshop in February 2017. The school has been seen as a great developing searches in new final states, many of them quite difficult success, particularly for new students, who receive a strong grounding to reconstruct. This work has already begun, using Run 1 data as in experimental and theoretical aspects of particle physics. a test bed. During 2017, the focus will shift to Run 2 data, where the higher collision energy provides opportunities through harder Outreach momentum spectra and larger rates, and further challenges through In 2017, CoEPP will continue its highly successful high-school programs: tighter trigger conditions for reconstructing exotic meson decays. international masterclass and work experience week. In addition, the This work complements preparations being carried out by CoEPP Centre is planning a Year 9 Science Camp for students from four key experimentalists for the future Belle II project. high schools in the Northern Grampians Shire in September 2017. This will be based on the dual themes of particle physics and astronomy to demonstrate how these different areas of science link and complement each other.

80 LOOKING AHEAD ANNUAL REPORT

Stakeholder and end user On the political level, in October 2016 we met with Minister Hunt during the Fermilab initiative in Chicago, and in 2017 are continuing interactions to engage with Minister Sinodinos and the Chief Scientist of Australia, Alan Finkel, with regard to enhancing the opportunities for CoEPP undertakes a broad program of interactions with stakeholders high-energy physics research in Australia. and end users. Our primary stakeholder is CERN, where a large amount of research from our Melbourne, Adelaide and Sydney nodes In 2017, we will have increasing engagement with Australian is undertaken. Recent initiatives within CoEPP have also begun to industry through initiatives such as the Stawell Underground Physics explore the opportunities that would be available to CoEPP and to Laboratory (SUPL) and the SABRE direct detection dark matter Australian Industry through formal participation with CERN through experiment, which is to be located in the laboratory. Additionally, our Associate Membership. This initiative would allow Australia to bid on growing involvement with medical physics research in areas such as industrial contracts, participate in technology transfer arrangements, hadron therapy, through the University of Melbourne, continue to allow Australian citizens to be appointed to CERN staff positions and provide ongoing opportunities. broaden our range of scientific participation within CERN. Other scientific initiatives, reported elsewhere in this annual report, are our formal links with Fermilab and IHEP, which provide growing worldwide awareness of the capability of CoEPP and additional opportunities for expanding our stakeholder base.

81 LOOKING AHEAD ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE

Case study: Searching for new physics with computer vision

The use of machine learning, and neural networks in boson decays. One model included in this study particular, has a long history in particle physics, and was developed by Dr Peter Skands and Nadine the idea of using neural networks for quark–gluon Fischer at Monash University (Eur. Phys. J. C 76, 589). discrimination, Higgs tagging and track identification Differences in network performance were no larger goes back over 25 years. However, the development than differences observed when using traditional of efficient deep neural networks and the computing identification variables. The published result power associated with graphics processing units (Phys. Rev. D 95, 014018) will help strengthen the mean that image recognition technology has foundation for future studies in this area. become extremely powerful, driving the resurgence in interest in these techniques. At the increased LHC collision energy, the ATLAS and Figure 1 CMS experiments have the ability to search for new Jet image generation particles at even higher masses. This is not without in ATLAS detector. challenge, however, as these heavy particles produce narrow clusters of high-momentum Standard Model particles that can be difficult to resolve and separate from the vast background of similar signatures. The ATLAS and CMS detectors house calorimeters made of concentric cylindrical grids of cells, each measuring an electrical pulse proportional to the energy deposited by particles. They essentially capture three-dimensional cylindrical pictures of pixelised sums of particle energies around a proton– proton collision. The complex hierarchical learning models used to recognise objects such as written text or human faces in an image, or autonomously drive a vehicle, are therefore ideally suited to extract the information from LHC collisions that are critical in the search for new physics. These so-called deep learning methods also have the potential to identify new physical properties not yet exploited by current methods. Figure 2 The past decade has seen an explosion of interest in understanding the structure within these calorimeter Jet image for hadronic signals created by the decay of high-momentum W boson. particles at the LHC. The ability to identify the hadronic decay products of a wide variety of particles is crucial in both the analysis of Standard Model processes and searches for new physics. It will become even more important as the LHC runs at higher energies and with future colliders on the horizon. New approaches involve the application of machine learning techniques at the forefront of computer vision. After detector signals are processed into pixelated images, deep neural networks can be trained to discriminate between a signal and background. At the University of Melbourne, Dr James Barnard, Dr Noel Dawe, Dr Matthew Dolan and CoEPP student Nina Rajcic investigated how the modelling variations across three major proton–proton collision simulation software implementations affect the performance of a deep neural network using calorimeter images created by hadronic W

82 LOOKING AHEAD

Disclaimer The ARC Centre of Excellence for Particle Physics at the Terascale (CoEPP) has used its best endeavours to ensure that material contained in this publication was correct at the time of printing. Authorisation CoEPP Advisory Board and Executive Committee. April 2017. Images Courtesy of ATLAS Experiment, Casamento photography, CERN, Frank DeLaRambelya, Caroline Hamilton, Daniel Linnet, Steve Morton, Laura Vanags, Royal Society of Victoria, Fermilab, IHEP and IUPAP Secretariat. Design Biotext, Canberra

ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE CoEPP ANNUAL REPORT 2015

ARC Centre of Excellence for Particle Physics at the Terascale

ANNUAL REPORT 2016 ANNUAL www.coepp.org.au REPORT B 16