DOCSLIB.ORG

The Search for Top-Squark Pair Production with the ATLAS Detector

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Search for Top-Squark Pair Production with the ATLAS Detector DISSERTATION The Search for Top-Squark Pair Production with the ATLAS Detector at ps = 13 TeV in the Fully Hadronic Final State Philipp Mogg Fakultät für Mathematik und Physik Albert-Ludwigs-Universität Freiburg The Search for Top-Squark Pair Production with the ATLAS Detector at ps = 13 TeV in the Fully Hadronic Final State Dissertation zur Erlangung des Doktorgrades der Fakultät für Mathematik und Physik der ALBERT-LUDWIGS-UNIVERSITÄT Freiburg im Breisgau vorgelegt von Philipp Mogg Dezember 2019 DEKAN: Prof. Dr. Wolfgang Soergel BETREUER DER ARBEIT: Prof. Dr. Karl Jakobs, Dr. Christian Weiser ERSTGUTACHTER: Dr. Christian Weiser ZWEITGUTACHTER: Prof. Dr. Marc Schumann Datum der mündlichen Prüfung: 21.02.2020 PRÜFER: Dr. Christian Weiser Prof. Dr. Gregor Herten Prof. Dr. Stefan Dittmaier “Scientific revolutions don’t change the universe. They change how humans interpret it.” —The Science of Discworld: Judgement Day, by Terry Pratchett († 2015) Contents 1 Introduction1 2 Theory background3 2.1 The Standard Model . .3 2.1.1 Structure . .4 2.1.2 Particle content . .5 2.1.3 The Standard Model Lagrangian . .7 2.1.4 The Brout-Englert-Higgs mechanism . 11 2.2 Supersymmetric extensions . 15 2.2.1 Motivation . 16 2.2.2 General structure . 19 2.2.3 The MSSM . 23 2.2.4 Top-Squark phenomenology at the LHC . 28 3 Experiment 33 3.1 The LHC machine . 33 3.2 The ATLAS detector . 36 3.2.1 Inner detector . 39 3.2.2 Calorimeter . 41 3.2.3 Muon spectrometer . 43 3.2.4 Trigger system . 44 i Contents 4 Event Reconstruction 47 4.1 Track and vertex reconstruction . 48 4.2 Calorimetric clusters . 50 4.3 Muons . 51 4.4 Electrons and photons . 54 4.5 Hadronic jets . 55 4.6 b-tagging . 59 4.7 Missing transverse momentum . 60 4.8 Physics validation . 62 5 Search for top squarks in the fully hadronic final state 65 5.1 Data collection and trigger . 67 5.2 Simulated data . 71 5.3 Object definitions . 75 5.4 Discriminating variables . 79 5.5 Signal regions . 89 5.6 Background estimation . 100 5.6.1 One-lepton backgrounds . 103 5.6.2 Z+jet background . 107 5.6.3 tt¯ + Z background . 110 5.6.4 Multijet background . 112 5.7 Systematic Uncertainties . 115 5.7.1 Experimental uncertainties . 115 5.7.2 Theory uncertainties . 118 5.8 Statistical interpretation . 122 5.9 Results . 125 6 Studies with new methods 139 6.1 Top identification . 139 6.1.1 Large-R-jet tagging . 140 ii Contents 6.2 Top identification in semi-boosted scenarios . 147 6.3 Conclusions of top identification study . 150 miss 6.4 Object-based ET significance . 150 6.5 Signal region optimisation . 151 6.5.1 SRA optimisation . 153 6.5.2 SRB optimisation . 157 7 Conclusion 163 8 Acknowledgements 165 Bibliography 169 iii 1 Introduction The understanding of the most fundamental objects and their behaviour and interactions has been a dream of many a scientist. Much progress in that regard was made in the twentieth century, starting with quantum mechanics and special relativity, and subsequently quantum field theory which combines the two, accompanied by progress in mathematics like the understanding of symmetries, all of which have fundamentally changed the way we interpret the universe. This lead to a long line of experimental discoveries in particle physics and continuously new theoretical interpretations to match those. The conclusion of this effort is today known as the Standard Model of Particle Physics, a theory that describes all experimentally observed particles and fundamental forces except gravity. The Standard Model has withstood all attempts to directly contradict it for a long time, and all its prediction have been proved true, with the discovery of the Higgs Boson by the ATLAS and CMS collaborations [1, 2] having delivered the last piece. However, since the Standard Model does not describe gravity and cannot explain other cosmological findings, we must assume that the Standard Model is not a full description of the universe. Other hints, like extreme fine-tuning of constants in the theoretical description, lead to the interpretation of the Standard model as the low-energy representation of a more fundamental theory. For these reasons, the search for new physics at unprecedented energy scales was one of the main goal in the building of ATLAS and the Large Hadron Collider. Supersymmetry is a prominent and well-studied theory which can address several of the shortcomings of the Standard Model. It postulates a symmetry between the two classes of particles – bosons, which have an integer spin, and fermions, which have a half-integer spin. 1 1 Introduction This would lead to a whole new family of particles, which could be at an energy scale that is reachable with the LHC; therefore a rich search program exists at ATLAS. This thesis describes a search for the supersymmetric partner of the top quark – the top squark. We are looking for events where a top-squark pair is produced in a proton-proton collision at a centre- of-mass energy of 13 TeV; the unstable top-squarks then decay in several steps into light- and heavy-flavour quarks and neutralinos – another type of hypothetical supersymmetric particle which leaves the detector without a trace – leading to a detector signature with a multitude of hadronic jets, including b-jets, and missing transverse momentum. A similar search was already conducted with data taken during Run 1 of the LHC at ps = 8TeV without finding any evidence for new physics [3]. The higher centre-of-mass energy and luminosity during LHC Run 2 and also improved detector performance and analysis techniques allow to greatly extend the sensitivity into areas that could not be excluded so far. The theoretical foundations are discussed in Chpt. 2, including the Standard Model and the possibility to expand the model with supersymmetry. The experimental set-up that was used to produce data, which is the Large Hadron Collider and the ATLAS detector, is described in Chpt. 3. The methods to reconstruct physics objects from the raw detector data are described in Chpt. 4. A search for top squarks was conducted with data taken in 2015 and 2016 at ps = 13TeV [4] with major contributions by the author; this is described in Chpt. 5, including the strategies to define search regions with a high potential purity of signal events, the methods to estimate Standard Model backgrounds, the evaluation of systematic uncertainties and finally the results and interpretation of the search. Only part of the Run-2 data was analysed in this context yet, a search with the full dataset is yet to follow this thesis; Chpt. 6 describes studies of new methods to improve the sensitivity that were conducted by the author. A conclusive summary is then given in Chpt. 7. 2 2 Theory background This chapter describes the theory behind the physics discussed in this thesis. Our current best knowledge about elementary particle physics is the Standard Model, which is described in Sec. 2.1. Section 2.2 then describes Supersymmetry as a possible extension to the Standard Model, which has the potential to solve several of the shortcomings (discussed in Sec. 2.2.1) that the Standard Model has despite its undeniable usefulness. 2.1 The Standard Model The Standard Model of particle physics (SM) describes our current understanding of all known fundamental particles and their interactions, with the exception of gravity. It is a quantum field theory (QFT), a framework that combines special relativity and quantum mechanics. The basic principles and notations of QFT are described in [5]. The SM emerged in the 1960s and 1970s as a result of the work of many physicists describing the strong interaction and the electroweak theory, which is a unified description of the electromagnetic and the weak interaction. The SM has since been extremely successful in making predictions and withstanding experimental tests and is still our best description of fundamental particles and interactions. The description given here is a summary of information that can be found in [5–7], if not stated otherwise. 3 2 Theory background 2.1.1 Structure The strong and electroweak interaction are described by the exchange of spin-1 particles (gauge bosons) which are quanta of gauge fielda. These bosons can carry mass as well as charges. QFT is based on Lagrangian mechanics and makes use of Hamilton’s principle. This means that a system behaves always in a way so that the action functional Z 4 S = d x L F;¶m F (2.1) becomes extremal. A system is therefore completely described by its Lagrangian density L , in the following simply called Lagrangian, which is a function of the quantum field F(x) at a space-time point x, and its first derivative ¶m F(x). The Euler-Lagrange equation gives the equations of motion: " # ¶L ¶ ¶L : m = 0 (2.2) ¶F − ¶x ¶ ¶m F The SM is a gauge theory, which means that the Lagrangian must be invariant under a continuous group of local transformations (Lie group). According to the Noether Theorem, each symmetry (under global or local transformation) is always associated with a conserved quantity [8]. The SM is composed of the theory of Quantum Chromodynamics (QCD), which describes the strong interaction [9], and the Glashow-Salam-Weinberg theory of electroweak interaction [10,11]. QCD is described by the Lie group SU(3), with the colour charge C being the conserved quantity of this symmetry. The electroweak theory imposes a SU(2) U(1) ⊗ symmetry. The SU(2) group is associated with the conservation of the third component of the weak isospin T3; the U(1) group leads to conservation of the weak hypercharge YW .
Load more

Recommended publications
  • Standard Model and Measurements of Its Parameters (Like the Mass of the Top Quark) at Hadron Colliders Are Presented
    Title: Physics at Hadron Colliders Lecturer: Dr Karl Jakobs Date and Times: 1st August at 11:15 2nd August at 10:15 3rd August at 10:15 3rd August at 11:15 Summary of the proposed talk: Present and future hadron colliders play an important role in the investigation of fundamental questions of particle physics. After an introductory lecture, tests of the Standard Model and measurements of its parameters (like the mass of the top quark) at hadron colliders are presented. In addition, it will be discussed how the Higgs boson can be searched for at hadron colliders and how "New Physics", i.e. physics beyond the Standard Model, can be explored. Results are presented from the currently ongoing run at the Tevatron proton antiproton collider at the US research lab Fermilab. In addition, the rich physics potential of the experiments at the CERN Large Hadron Collider is discussed. Prerequisite knowledge and references: - The Standard Model (Lecture by A. Pich) - Beyond the Standard Model (Lecture by E. Kiritsis) Biography- Brief CV: Dr Karl JAKOBS -Studied Physics at the University of Bonn, Germany - Summer student at CERN in 1984 - PhD at the University of Heidelberg, in 1988 Thesis on the UA2-Experiment at the CERN Proton-Antiproton Collider (already Hadron Collider physics at that time) - Fellow and staff position at CERN, UA2 experiment - 1992 - 1996 Max-Planck-Institute for Physics, Munich ALEPH and ATLAS experiments - 1996 - 2003 Prof. of physics at the University of Mainz ALEPH and ATLAS experiments - Since 2000: participation in the D0-Experiment at the Tevatron HR-RFA 07/06 - Since 2003: Prof.
    [Show full text]
  • Die Entdeckung Des Higgs-Teilchens Am CERN
    Die Entdeckung des Higgs-Teilchens am CERN Prof. Karl Jakobs Physikalisches Institut Universität Freiburg From the editorial: “The top Breakthrough of the Year – the discovery of the Higgs boson – was an unusually easy choice, representing both a triumph of the human intellect and the culmination of decades of work by many thousands of physicists and engineers.” Nobel-Preis für Physik 2013: François Englert und Peter Higgs “ … for the theoretical discovery of a mechanism that contributes to our understanding of the origin of mass of sub-atomic particles, and which recently was confirmed through the discovery of the predicted fundamental particle, by the ATLAS and CMS experiments at CERN’s Large Hadron Collider.” EPS Prize 2013: The 2013 High Energy and Particle Physics Prize, for an outstanding contribution to High Energy Physics, is awarded to the ATLAS and CMS collaborations, “for the discovery of a Higgs boson, as predicted by the Brout-Englert-Higgs mechanism”, and to Michel Della Negra, Peter Jenni, and Tejinder Virdee, “for their pioneering and outstanding leadership rôles in the making of the ATLAS and CMS experiments”. Physik-Journal Februar 2015: “.. Obwohl in diesen großen Kollaborationen eine große Zahl von Forschern mitarbeitet, ist es möglich, einzelne Forscherpersönlichkeiten herauszuheben, deren Ideen und Arbeit für den Erfolg des Experiments von besonderer Bedeutung waren. Zu diesen gehört neben den Sprechern der Experimente Karl Jakobs.” The Standard Model of Particle Physics γ mW ≈ 80.4 GeV mZ ≈ 91.2 GeV (i) Matter particles: quarks and leptons (spin ½, fermions) (ii) Four fundamental forces: described by quantum field theories (except gravitation) à massless spin-1 gauge bosons (iii) The Higgs field à scalar field, spin-0 Higgs boson The Brout-Englert-Higgs Mechanism F.
    [Show full text]
  • Phd Position at the University of Freiburg (ATLAS Experiment)
    PhD position at the University of Freiburg (ATLAS experiment) We are seeking a highly motivated and enthusiastic PhD candidate to conduct research at the interface between particle physics and cosmology in the ATLAS experiment at the Large Hadron Collider at CERN. The main topic of the position will be the search for heavy Higgs bosons, which will shed light on the connection between the Higgs sector and the matter-antimatter asymmetry in the Universe. Work on the improvement of the identification of b-jets or Monte-Carlo event generators is also foreseen. Participation in the operation of the ATLAS detector with frequent travels to CERN is expected. The position will be based at Freiburg. Applicants should hold or be about to obtain a Master's degree with excellent grades in particle physics and be highly motivated to work in an international research environment. Familiarity with computer programming (especially C++ and/or Python) and analysis software frameworks like ROOT is expected. The position is expected to begin as soon as possible. Applications which are com- plete and will be received until November 30 will be given full consideration, however applications will continue to be processed until the position has been filled. The application documents should be sent directly to [email protected] and should include the following documents: • curriculum vitae • cover letter stating the research interests and motivation to become part of the programme • copy of Master's and Bachelor diplomas • official grade transcripts of Master's and Bachelor diplomas with a description of the grading scheme • copy of Master's thesis • two letters of recommendation which should be sent by the referees to the above email address The successful candidate will be integrated in the Emmy-Noether independent junior research group \The Higgs boson as a window to the Dark Universe", which aims to exploit the recently discovered Higgs boson in order to investigate the major open problems of the dark universe: baryogenesis, dark matter and dark energy.
    [Show full text]
  • The ATLAS Experiment at the LHC -Status and Expectations for Physics
    The ATLAS Experiment at the LHC -status and expectations for physics - • ATLAS Status and Commissioning • Expected first physics with ATLAS • Prospects for 1, 10 and 30 fb-1 - Top - Higgs Bosons - New Physics (a few examples) Karl Jakobs Physikalisches Institut University of Freiburg / Germany The role of the LHC 1. Explore the TeV mass scale - What is the origin of the electroweak symmetry breaking ? - The search for “low energy” supersymmetry - Other scenarios beyond the Standard Model - ……. Look for the “expected”, but we need to be open for surprises 2. Precise tests of the Standard Model This Talk (ATLAS): - There is much sensitivity to Physics Beyond the - Top Quark Physics Standard Model in the precision area - Higgs Searches - A few Exotica - Many Standard Model measurements can be used to test and to tune the detector performance J. Nash (CMS): - Standard Model (QCD, el.weak) - SUSY - More Exotica The ATLAS experiment Diameter 25 m Barrel toroid length 26 m End-cap end-wall chamber span 46 m Overall weight 7000 Tons A historical moment: Closure of the LHC beam pipe ring on 16th June 2008 ATLAS was ready for data taking in August 2008 ATLAS Commissioning with cosmic rays..... The very first beam-splash event from the LHC in ATLAS on 10th September 2008, 10:19 ….and beam related events Trigger timing with beam splash events Few days of beam halo and splash events helped enormously to adjust timing of different triggers 10 September 12 September ATLAS ATLAS 1 bunch crossing number = 25 ns K. Jakobs IFCA meeting, SLAC, Oct. 2008
    [Show full text]
  • Search for Squarks and Gluinos in Final State with Jets, Missing Transverse Momentum and Boosted W Bosons with the ATLAS Experiment
    Dissertation zur Erlangung des Doktorgrades der Fakultät für Mathematik und Physik der Albert-Ludwigs-Universität Freiburg im Breisgau Search for squarks and gluinos in final state with jets, missing transverse momentum and boosted W bosons with the ATLAS experiment von Tomáš Jav˚urek Betreut von Prof. Dr. Gregor Herten September 2016 Dekan: Prof. Dr. Dietmar Kröner Prodekan: Prof. Dr. Gregor Herten Referent: Prof. Dr. Gregor Herten Koreferent: Prof. Dr. Markus Schumacher Prüfer (Experiment): Prof. Dr. Karl Jakobs Prüfer (Theorie): Prof. Dr. Stefan Dittmaier Datum der mündlichen Prüfung: 20.6.2016 Erklärung Hiermit erkläre ich die vorliegende Arbeit selbständig und nur mit den angegebenen Quellen und Hilfsmitteln verfasst zu haben. Einige Ergebnisse dieser Arbeit wurden in den untenstehenden Publikationen bereits veröffentlicht. Freiburg, den 17.03.2016 Tomas Javurek Acknowledgements Firstly, I would like to thank to Zuzana Rurikova, who has been very patient with me as supervisor as well as colleague and friend. I would like to thank to my wife, colleague in the computing, partner in sport and life Martina Pagacova-Javurkova for cooperation, discussion, patience and great care. Thanks belong also to colleagues at University of Freiburg, primarily to Prof. Gregor Herten and Andrea Di Simone, for discussions, supervision, corrections of the thesis and also for providing me the best environment to study, teach and work as a scientist. The work presented here has been performed in collaboration with the ATLAS SUSY 0-lepton 2-6 jet analysis group. I would like to thank to all colleagues of this group, especially to Renaud Bruneliere, Marija Vranjes Miliosavljevic and Nikola Makovec.
    [Show full text]
  • Property Measurements of the Higgs Boson and Search for High Mass Resonances in Four-Lepton Final State with the ATLAS Detector at the LHC
    Property Measurements of the Higgs Boson and Search for High Mass Resonances in Four-Lepton Final State with the ATLAS Detector at the LHC by Nan Lu A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Physics) in The University of Michigan 2017 Doctoral Committee: Professor Bing Zhou, Chair Professor Finn Larsen Professor Homer A. Neal Professor Gregory Tarle Professor Ji Zhu Nan Lu [email protected] ORCID iD: 0000-0002-2631-6770 c Copyright by Nan Lu 2017 All Rights Reserved ACKNOWLEDGEMENTS First and foremost, I would like to express my deepest gratitude to my advisor Bing Zhou for her guidance and support though my Ph.D. study. Bing's vision, leadership, dedication and immense knowledge have deeply influenced me. I am extremely fortunate to have Bing as my advisor. Besides my advisor, I would like to thank other members of my thesis committee: Finn Larsen, Homer A. Neal, Gregory Tarle and Ji Zhu, for reviewing my thesis and providing very helpful and enlightening comments. I am very grateful for the opportunities to take the physics courses offered by Myron Campbell, Henriette Elvang, Emanuel Gull, Gordon L. Kane, David Luben- sky, Roberto D. Merlin, Leonard M. Sander, and Bing Zhou, which have helped me appreciate the beauty of physics and have laid the foundations for my research work. I would like to express my sincere gratitude to the Michigan ATLAS group. I thank Haijun Yang for teaching me the concepts and methods in physics analysis during my early time in the group.
    [Show full text]
  • Physics at Hadron Colliders -From the Tevatron to the LHC
    Physics at Hadron Colliders -From the Tevatron to the LHC- • Introduction to Hadron Collider Physics • The present Hadron Colliders - The Tevatron and the LHC - The experiments - Experimental issues (particle ID, ….) • Test of the Standard Model - QCD: Jet, W/Z, top-quark production - W and top-quark mass measurements • Search for the Higgs Boson Karl Jakobs • Search for New Phenomena Physikalisches Institut Universität Freiburg / Germany Building blocks of the Standard Model • Matter made out of fermions (Quarks and Leptons) • Forces electromagnetism, weak and strong force + gravity (mediated by bosons) • Higgs field needed to break (hide) the electroweak symmetry and to give mass to weak gauge bosons and fermions → Higgs particle 2 Theoretical arguments: m H < ~1000 GeV/c K. Jakobs Lectures, GK „ Masse, Spektrum, Symmetrie“ , Berlin, Sep. 2009 Where do we stand today? e+e- colliders LEP at CERN and SLC at SLAC + the Tevatron pp collider + HERA at DESY + many other experiments (fixed target…….) have explored the energy range up to ~100 GeV with incredible precision • The Standard Model is consistent Summer 2009 with all experimental data ! • No Physics Beyond the SM observed (except clear evidence for neutrino masses) • No Higgs seen (yet) Direct searches: (95% CL limits) 2 mH > 114.4 GeV/c 2 2 mH < 160 GeV/c or mH > 170 GeV/c Only unambiguous example of observed Higgs (P. Higgs, Univ. Edinburgh) Consistency with the Standard Model Sensitivity to the Higgs boson and other new particles via quantum corrections: Interpretation within the Standard Model (incl. new (2009) m W and m t measurements) 2 mH = 87 (+35) (-26) GeV/c 2 mH < 157 GeV/c (95 % CL) Constraints on the Higgs mass in a supersymmetric theory O.
    [Show full text]
  • Harvest of Run 1 Thomas Schörner-Sadenius Editor
    Thomas Schörner-Sadenius Editor Harvest of Run 1 The Large Hadron Collider Thomas Schörner-Sadenius Editor The Large Hadron Collider Harvest of Run 1 123 Editor Thomas Schörner-Sadenius Deutsches Elektronen-Synchrotron (DESY) Hamburg Germany ISBN 978-3-319-15000-0 ISBN 978-3-319-15001-7 (eBook) DOI 10.1007/978-3-319-15001-7 Library of Congress Control Number: 2015933362 Springer Cham Heidelberg New York Dordrecht London © Springer International Publishing Switzerland 2015 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. Cover art: Jorge Cham—www.phdcomics.com Printed on acid-free paper Springer International Publishing AG Switzerland is part of Springer Science+Business Media (www.springer.com) Foreword The Large Hadron Collider is the largest scientific experiment mankind ever devised, and already the first period of data-taking was a tremendous success.
    [Show full text]
  • Curriculum Vitae
    Curriculum Vitae Prof. Dr. Karl Jakobs Scientific Career: Dec. 1984: Diploma in Physics, Bonn University June 1988: PhD in Physics, University of Heidelberg, UA2 experiment at CERN 1988 – 1991: Fellow and staff member at the European Centre for Particle Physics, CERN, UA2 experiment 1991 – 1996: Scientific staff member at the Max-Planck-Institut für Physik in Munich 1996 - 2003: Professor (C3, Associate Professor) of Experimental Particle Physics at the University of Mainz Since April 2003: Professor (C4, Full Professor) of Experimental Particle Physics at the University of Freiburg Major current research activities: - Data analysis in the ATLAS experiment at the LHC (Measurement of Higgs boson parameters, Search for supersymmetric particles, Study of Standard Model processes) - Research and development for radiation hard silicon detectors (RD50 Collaboration) - Research and development for the construction of the upgraded silicon tracking detector for the ATLAS experiment at the High Luminosity LHC Major completed research activities: - UA2 Experiment, (1988 – 1992) Investigation of QCD effects in W production 0 - ALEPH Experiment, (1992 – 2000) Search for B s oscillations (LEP-I, 1993 – 1995) and for supersymmetric particles (1996 – 2000) - ATLAS Experiment, (since 1992) Detector development, Liquid argon calorimeter (at MPI Munich and in Mainz) and silicon tracking detectors (in Freiburg) - Significant contribution to the construction of the ATLAS SemiConducting Tracking de- tector (SCT) (Freiburg) - DØ Experiment at Fermilab/Chicago
    [Show full text]
  • The Search for Physics Beyond the Standard Model in Connection to Electroweak Symmetry Breaking
    The Search for Physics Beyond the Standard Model in Connection to Electroweak Symmetry Breaking A brief Summary Article in the Context of a Cumulative Habilitation Treatise Philip Bechtlea January 23, 2014 Abstract This article is a summary of – and a commentary on – developments in the interpre- tation of data from various aspects of physics beyond the Standard Model connected to electroweak symmetry breaking. A special focus is laid on the motivation of the Higgs mechanism, the critical evaluation of its virtues, and on the best motivated theories to stabilise electroweak symmetry breaking, based on Supersymmetry. The main targets of the article are the description of aspects of the direct and indirect search for the Higgs and for Supersymmetry, and the description of two sets of tools, their experimen- tal and theoretical input, and their most important results: First, HiggsBounds and HiggsSignals, two tools for model-independent tests of limits on and measurements of Higgs boson properties against predictions from any theory with Higgs-like states. Second, Fittino, a tool to make full use of the measurements from B-physics, preci- sion electroweak measurements, other precision data, cosmology, Higgs discovery, and cosmological measurements, to constrain Supersymmetry and/or other physics beyond the Standard Model. aPhysikalisches Institut, Universit¨at Bonn, Nussallee 12, 53115 Bonn, Germany 1 Contents 1 Introduction 5 2 Theories about the Fundamental Constituents of Nature 7 2.1 The Standard Model of Particle Physics: So near... ........ 7 2.2 ... andyetsofar................................. 11 2.3 Arethereanyalternatives,afterall? . ....... 12 3 Boundary Conditions: Precision Measurements and Cosmology 15 3.1 Precision measurements at lower energies .
    [Show full text]
  • Program + Abstracts Booklet
    28th Rencontres de Blois Particle Physics and Cosmology May 29th - June 3rd, 2016 Preliminary Program + Abstracts + List of Participants 1 Plenary Sessions MONDAY 09:00 Opening Session Jean Tranˆ Thanh Vanˆ Welcome Marc Gricourt Welcome address from the Mayor of Blois 10:30 First Session Chair: Karl Jacobs Karl Jakobs Introduction Gigi Rolandi Status / highlights of LHC Run 2 Aristeidis Noutsos Pulsars Bruce Allen Gravitational waves 12:30 Lunch 14:00 The Higgs Boson Chair: Gigi Rolandi Marc Escalier Higgs bosons: production and decays into bosons Michal Bluj Higgs boson parameters and fermionic decays Daniel Enrique de Status of Higgs precision studies Florian Sabaris Shinya Kanemura Extended Higgs sector 17:15 Conference Photograph 18:00 Visit of the Chateau de Blois 20:00 Dinner at the Chateau TUESDAY 09:00 QCD+EW+Top Physics+Heavy Ions Chair: Geraldine´ Servant Shima Shimizu Test of QCD at Colliders Aleko Khukhunaishvili Status of electroweak physics Maria Aldaya Martin Top Quark production and properties 11:00 QCD+EW+Top Physics+Heavy Ions Chair: Sebastien´ Descotes-Genon Barbara Jaeger Progress in precision calculation Eero Aleksi Kurkela Far-from-equilibrium plasmas 12:00 Beyond the Standard Model Physics Chair: Ian Brock Andrew J. Whitbeck Status of the Search for SUSY 12:30 Lunch 14:00 Beyond the Standard Model Physics Chair: Ian Brock Claire Lee Search for Exotics Bertrand Martin dit Search for TOP partner Latour Andrea Wulzer Implications of LHC results for BSM physics Geraldine´ Servant A cosmological solution to the hierarchy
    [Show full text]
  • Curriculum Vitae 1 Personal Details 2 Professional History 3 Education 4 Scientific Leadership 5 Awards
    Curriculum vitae 1 Personal details Name Prof. Nicola Giacinto Piacquadio Address Office D143, Physics Building Department of Physics and Astronomy State University of New York Stony Brook, NY 11794 Phone number +1 650 669 7296 2 Professional history 2016-present Assistant Professor at Stony Brook University (State University of New York) 2015-2016 SLAC Staff Scientist (continuing appointment) 2012-2015 SLAC Panofsky Fellow 2009-2012 CERN Research Fellow 3 Education 2005-2010 Ph.D. degree: Faculty of Physics, University of Freiburg (Germany) Graduation on 01. February 2010 with final grade “Summa cum laude” Thesis: “Identification of b-jets and investigation of the discovery potential of a Higgs boson in the WH ! lvbbbar channel with the ATLAS experiment”’ Advisor: Prof. Karl Jakobs, Freiburg University 2000-2005 Master degree: Faculty of Physics, “La Sapienza University” in Rome (Italy) Graduation on 14 July 2005 with final grade 110/110 cum laude Thesis: “B meson decays into three light pseudoscalars” Advisor: Prof. Fernando Ferroni, Rome University 1995-2000 High school: Ginnasio “V. Lanza” in Foggia (Italy) Graduated with final mark 100/100 4 Scientific leadership Oct 2018-Sep 2020 Convener of the ATLAS Higgs Working group (>400 members) Oct 2014-Sep 2016 Convener of the ATLAS flavor-tagging group (∼80 members) Oct 2013-Sep 2014 Convener of H ! b¯b subgroup of ATLAS Higgs Working group (∼60 members) Oct 2012-Sep 2013 Contact person for b-tagging in the Higgs Working Group 2011-2013 ATLAS coordinator of the VH sub-group of the Higgs cross section WG 2010-2011 Convener of the ATLAS Pixel Clusterization Task Force (12 members) 2008-2011 Responsible for the ATLAS primary and secondary vertex reconstruction software 5 Awards • W.
    [Show full text]