Physics and Astronomy ANNUAL REVIEW 2013–14 UCL DEPARTMENT of PHYSICS and ASTRONOMY
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Annual Review 2008 1
UCL DEPARTMENT OF PHYSICS AND ASTRONOMY PHYSICS AND ASTRONOMY ANNUAL REVIEW 2008 Contents Introduction 1 Students 2 Careers 5 Highlights and News 8 Astrophysics 17 High Energy Physics 19 Atomic, Molecular, Optical and Position Physics 21 Condensed Matter and Material Physics 25 Grants and Contracts 27 Publications 31 Staff 40 Cover image: Threaded molecular wire This image was produced by Dr Sergio Brovelli and refers to recent results obtained by the group of Professor Franco Cacialli. The molecular wire consists of a semiconducting conjugated polymer supramolecularly encapsulated (i.e. with no covalent bonds) into cyclodextrin macrocycles (in green). This class of organic functional materials gives highly controllable optical properties and higher luminescence efficiency when employed as the active layer in light-emitting diodes. The supramolecular shield prevents potentially detrimental intermolecular interactions and preserves single-molecule photophysics even at high concentration. PHYSICS AND ASTRONOMY ANNUAL REVIEW 2008 1 Introduction in trying to help pilot STFC through maintaining a flourishing Department. very choppy waters and as major It is therefore with particular pleasure recipients of their funding support. Our that I note the award of no less than six Astrophysics group were particularly long-term Fellowships to young scientists unfortunate in the timing of the crisis, wishing to start their independent as it arrived just as the majority of the academic careers at UCL, see page 8. groups funding was due to be renewed. These Fellowships are deeply UCL has moved to ensure that years competitive as they attract world wide of research excellence in fundamental attention resulting in success rates of physics are not destroyed by what I hope 5% or less. -
LEP Experiments Take Shape
LEP experiments take shape Excavation of the 27 kilometre the LEP Experiments Committee, at work in Shanghai cutting and tunnel and vast underground cav which carefully monitors the pro polishing the BGO crystals for the erns for CERN's new LEP electron- gress of these projects. L3 electromagnetic calorimeter positron collider is forging ahead, One impressive aspect of the before sending them to CERN for and equipment for the machine is work is the development of inge acceptance tests. arriving on the site in increasing nious tooling, often using sophis After apologizing for having no quantities ready to attack the huge ticated techniques, to facilitate video to show, ALEPH spokesman task of installation (see April issue, construction and assembly of the Jack Steinberger stressed the diffi page 1). detector components. culties of fashioning an electro At about the same time that LEP For L3, spokesman Sam Ting magnetic calorimeter with its acre construction work began at CERN described how assembly of the and a half (6000 square metres) in 1983, physicists from some huge 7000-ton magnet to surround of wire planes containing hundred research centres through the detector continues to make 750 000 wires and millions of con out the world began gearing up satisfactory progress with comple nections. for the detailed design, construc tion of coil segments at CERN Meanwhile other parts of the tion and testing of the millions of keeping step with the supply of detector are coming together components for the four big detec steel from the Soviet Union. Pro smoothly. Winding of the super tors - ALEPH, DELPHI, L3 and duction lines are being set up for conducting magnet will soon get OPAL - which will study LEP's the high precision drift chamber underway at Saclay in France, electron-positron collisions. -
Supplemental Material for Molecular Simulations of Heterogeneous Ice
Supplemental Material for Molecular simulations of heterogeneous ice nucleation I: Controlling ice nucleation through surface hydrophilicity Stephen J. Cox,1, 2 Shawn M. Kathmann,3 Ben Slater,1 and Angelos Michaelides1, 2, a) 1)Thomas Young Centre and Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, U.K. 2)London Centre for Nanotechnology, 17{19 Gordon Street, London WC1H 0AH, U.K. 3)Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States (Dated: 22 April 2015) This Supplemental Material contains further details of the simulation methods and the data fitting procedure used. A movie and still images of a nucleation event at the NP with Eads=∆Hvap ≈ 0:9 are also provided. a)Electronic mail: [email protected] 1 I. FURTHER SIMULATIONS DETAILS To construct the NP, the ASE package1 was used: 6 atomic layers were used in the f1,0,0g family of directions; 9 layers in the f1,1,0g family; and 5 layers in the f1,1,1g family, except along the (1¯; 1¯; 1)¯ direction where no layers were used. As the equations of motion for the atoms in the NP were not integrated (i.e. they were fixed) no interaction potential was defined between them, and the adsorption energy Eads of a water monomer to the NP was therefore simply defined as the total energy after geometry optimization of a single water molecule at the center of the (111) face. The velocity Verlet algorithm was used to propagate the equations of motion of the water molecules, using a 10 fs time step. -
Mark Thomson Career History 2008 – : Professor of Experimental Particle Physics, University of Cambridge
Mark Thomson Career History 2008 – : Professor of Experimental Particle Physics, University of Cambridge. 2004 – 2008: Reader in Experimental Particle Physics, University of Cambridge. 2000 – 2004: University Lecturer (Physics), University of Cambridge. 1996 – 2000: CERN Staff Research Physicist, CERN. 1994 – 1996: CERN Fellow, CERN. 1992 – 1994: Research Fellow, University College London. 1988 – 1991: D. Phil. in Experimental Astroparticle Physics (Soudan 2), University of Oxford. 1985 – 1988: B. A. Physics, University of Oxford. Career Summary My research career has focused on neutrino physics, electroweak physics at electron-positron colliders, calorimetry and the development of advanced analysis/reconstruction techniques. My current research focus is on LBNF and the Fermilab SBN programme (MicroBooNE and LAr1-ND). Previously I worked on oscilla- tion physics with the MINOS experiment (νµ disappearance, νe appearance and atmospheric neutrinos) and the OPAL experiment at the Large-Electron-Positron (LEP) collider at CERN, where I led several of the key measurements of the properties of the W and Z bosons. I have a strong interest in calorimetric techniques for particle physics and I am one of the pioneers of Particle Flow Calorimetry that lies at heart of many concepts for future collider detectors. I am passionate about the teaching of physics and recently published my first book “Modern Particle Physics”. Research Management I have held a number of positions of responsibility, the most significant are listed below: 2014 – 2015: Member of the LBNF Interim Executive Board. 2014 – : LBNF-UK Principal Investigator. 2013 – 2015: Elected member of the LBNE Executive Board. 2013 – 2015: Member of the Linear Collider Collaboration (Physics & Detector) Executive Board. -
CONTENTS Group Membership, January 2002 2
CONTENTS Group Membership, January 2002 2 APPENDIX 1: Report on Activities 2000-2002 & Proposed Programme 2002-2006 4 1OPAL 4 2H1 7 3 ATLAS 11 4 BABAR 19 5DØ 24 6 e-Science 29 7 Geant4 32 8 Blue Sky and applied R&D 33 9 Computing 36 10 Activities in Support of Public Understanding of Science 38 11 Collaborations and contacts with Industry 41 12 Other Research Related Activities by Group Members 41 13 Staff Management and Implementation of Concordat 41 APPENDIX 2: Request for Funds 1. Support staff 43 2. Travel 55 3. Consumables 56 4. Equipment 58 APPENDIX 3: Publications 61 1 Group Membership, May 2002 Academic Staff Dr John Allison Senior Lecturer Professor Roger Barlow Professor Dr Ian Duerdoth Senior Lecturer Dr Mike Ibbotson Reader Dr George Lafferty Reader Dr Fred Loebinger Senior Lecturer Professor Robin Marshall Professor, Group Leader Dr Terry Wyatt Reader Dr A N Other (from Sept 2002) Lecturer Fellows Dr Brian Cox PPARC Advanced Fellow Dr Graham Wilson (leave of absence for 2 yrs) PPARC Advanced Fellow James Weatherall PPARC Fellow PPARC funded Research Associates∗ Dr Nick Malden Dr Joleen Pater Dr Michiel Sanders Dr Ben Waugh Dr Jenny Williams PPARC funded Responsive Research Associate Dr Liang Han PPARC funded e-Science Research Associates Steve Dallison core e-Science Sergey Dolgobrodov core e-Science Gareth Fairey EU/PPARC DataGrid Alessandra Forti GridPP Andrew McNab EU/PPARC DataGrid PPARC funded Support Staff∗ Phil Dunn (replacement) Technician Andrew Elvin Technician Dr Joe Foster Physicist Programmer Julian Freestone -
MITOCW | L0.3 Introduction to Nuclear and Particle Physics: Teaching Staff
MITOCW | L0.3 Introduction to Nuclear and Particle Physics: Teaching Staff MARKUS Welcome to this short recording of our 8.701 lecture. With this short discussion, I want to introduce the teaching KLUTE: staff to this course, the instructor, which is myself, Markus Klute, and our TA Justin. So I am faculty in the physics department since 2009. I received my diploma, which is my undergraduate study, in Germany and also my PhD from the University in Bonn. I-- with research on the OPAL experiment, which is an experiment on the large electron positron collider at CERN, on the ATLAS experiment, which is in the Large Hadron Collider, also at CERN, and also on the D0 experiment, which was one of the experiments at the Tevatron in Chicago at Fermilab. So after my PhD, I joined MIT as a postdoc, and later as a research scientist. And I worked on the CDF experiment at the Tevatron and the CMS experiment at the Large Hadron Collider. In 2007, I accepted a faculty position in Germany, where I spent about a year, before coming back to MIT. It's not a surprise-- this is CV-- that I-- my interest is in particle physics at the energy frontier. I work on design, the construction, the commissioning of detectors. We made major contribution to the hydronic calorimeter in CMS and also the data acquisition system. Most recently, I was leading the software and computing project within the CMS experiment. Most exciting-- the physics. And in 2012, we were able to discover the Higgs boson with the CMS experiment. -
Muon Bundles As a Sign of Strangelets from the Universe
Draft version October 19, 2018 Typeset using LATEX default style in AASTeX61 MUON BUNDLES AS A SIGN OF STRANGELETS FROM THE UNIVERSE P. Kankiewicz,1 M. Rybczynski,´ 1 Z. W lodarczyk,1 and G. Wilk2 1Institute of Physics, Jan Kochanowski University, 25-406 Kielce, Poland 2National Centre for Nuclear Research, Department of Fundamental Research, 00-681 Warsaw, Poland Submitted to ApJ ABSTRACT Recently the CERN ALICE experiment, in its dedicated cosmic ray run, observed muon bundles of very high multiplicities, thereby confirming similar findings from the LEP era at CERN (in the CosmoLEP project). Originally it was argued that they apparently stem from the primary cosmic rays with a heavy masses. We propose an alternative possibility arguing that muonic bundles of highest multiplicity are produced by strangelets, hypothetical stable lumps of strange quark matter infiltrating our Universe. We also address the possibility of additionally deducing their directionality which could be of astrophysical interest. Significant evidence for anisotropy of arrival directions of the observed high multiplicity muonic bundles is found. Estimated directionality suggests their possible extragalactic provenance. Keywords: astroparticle physics: cosmic rays: reference systems arXiv:1612.04749v2 [hep-ph] 17 Mar 2017 Corresponding author: M. Rybczy´nski [email protected], [email protected], [email protected], [email protected] 2 Kankiewicz et al. 1. INTRODUCTION Cosmic ray physics is our unique source of information on events in the energy range which will never be accessible in Earth-bound experiments Dar & De Rujula(2008); Letessier-Selvon & Stanev(2011). This is why one of the most important aspects of their investigation is the understanding of the primary cosmic ray (CR) flux and its composition. -
Trigger and Data Acquisition
Trigger and data acquisition N. Ellis CERN, Geneva, Switzerland Abstract The lectures address some of the issues of triggering and data acquisition in large high-energy physics experiments. Emphasis is placed on hadron-collider experiments that present a particularly challenging environment for event se- lection and data collection. However, the lectures also explain how T/DAQ systems have evolved over the years to meet new challenges. Some examples are given from early experience with LHC T/DAQ systems during the 2008 single-beam operations. 1 Introduction These lectures concentrate on experiments at high-energy particle colliders, especially the general- purpose experiments at the Large Hadron Collider (LHC) [1]. These experiments represent a very chal- lenging case that illustrates well the problems that have to be addressed in state-of-the-art high-energy physics (HEP) trigger and data-acquisition (T/DAQ) systems. This is also the area in which the author is working (on the trigger for the ATLAS experiment at LHC) and so is the example that he knows best. However, the lectures start with a more general discussion, building up to some examples from LEP [2] that had complementary challenges to those of the LHC. The LEP examples are a good reference point to see how HEP T/DAQ systems have evolved in the last few years. Students at this school come from various backgrounds — phenomenology, experimental data analysis in running experiments, and preparing for future experiments (including working on T/DAQ systems in some cases). These lectures try to strike a balance between making the presentation accessi- ble to all, and going into some details for those already familiar with T/DAQ systems. -
Coulomb Gluons and Colour Evolution
Coulomb gluons and colour evolution René Ángeles-Martínez in collaboration with Jeff Forshaw Mike Seymour JHEP 1512 (2015) 091 DPyC, BUAP & arXiv:1602.00623 (accepted for publication) 2016 In this talk: Progress towards including the colour interference of soft gluons in partons showers. PDF Hard process (Q) Parton Shower: Approx: Collinear + Soft radiation Q qµ ⇤ QCD Underlying event Hadronization Hadron-Hadron collision, Soper (CTEQ School) … 2 Motivation • Why? Increase precision of theoretical predictions for the LHC • Is this necessary? Yes, for particular non-inclusive observables. • Are those relevant to search for new physics? Yes, these can tell us about the (absence of) colour of the production mechanism (couplings). 3 Outline • Coulomb gluons, collinear factorisation & colour interference. • Concrete effect: super-leading-logs. • Including colour interference in partons showers. (Also see JHEP 07, 119 (2015), arXiv:1312.2448 & 1412.3967) 4 One-loop in the soft approximation kµ Q ⌧ ij Hard subprocess is a vector Colour matrices acting on 2 colour + spin d d k ↵ pi pj ig2T T − · 2 s i · j (2⇡)d [p k i0][ p k i0][k2+i0] Z j · ± − i · ± ↵ i : i0 i :+i0 i : i0 − − j : i0 j :+i0 j :+i0 − 2 ↵ Introduction: one-loop soft gluon correction After contour integration: d4k (2⇡)δ(k2)✓(k0) (2⇡)2δ(p k)δ( p k) g2µ2✏T T p p + iδ˜ i · − j · 2 s i · j i · j (2⇡)4 [p k][p k] ij 2[k2] Z j · i · ↵ (On-shell gluon: Purely real) (Coulomb gluon: Purely imaginary) 1ifi, j in , ˜ δij = 81ifi, j out , <>0 otherwise. -
What Makes a Good Descriptor for Heterogeneous Ice Nucleation on OH-Patterned Surfaces
What Makes a Good Descriptor for Heterogeneous Ice Nucleation on OH-Patterned Surfaces Philipp Pedevilla Thomas Young Centre and London Centre for Nanotechnology, 17-19 Gordon Street, London, WC1H 0AH, United Kingdom and Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, United Kingdom Martin Fitzner and Angelos Michaelides∗ Thomas Young Centre and London Centre for Nanotechnology, 17-19 Gordon Street, London, WC1H 0AH, United Kingdom and Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT, United Kingdom (Dated: October 5, 2018) Freezing of water is arguably one of the most common phase transitions on Earth and almost always happens heterogeneously. Despite its importance, we lack a fundamental understanding of what makes substrates efficient ice nucleators. Here we address this by computing the ice nucleation (IN) ability of numerous model hydroxylated substrates with diverse surface hydroxyl (OH) group arrangements. Overall, for the substrates considered, we find that neither the symmetry of the OH patterns nor the similarity between a substrate and ice correlate well with the IN ability. Instead, we find that the OH density and the substrate-water interaction strength are useful descriptors of a material's IN ability. This insight allows the rationalization of ice nucleation ability across a wide range of materials, and can aid the search and design of novel potent ice nucleators in the future. I. INTRODUCTION ing and ice formation on well-defined atomically flat sur- faces [10, 11], but these experiments are currently not ap- Nucleation is a process that plays a pivotal role in nu- plicable under atmospherically relevant conditions. -
Public Request to Take Stronger Measures of Social Distancing Across the UK with Immediate Effect 14Th March 2020
Public request to take stronger measures of social distancing across the UK with immediate effect 14th March 2020 (last update: 15th March 2020, 18:25) As scientists living and working in the UK, we would like to express our concern about the course of action announced by the Government on 12th March 2020 regarding the Coronavirus outbreak. In particular, we are deeply preoccupied by the timeline of the proposed plan, which aims at delaying social distancing measures even further. The current data about the number of infections in the UK is in line with the growth curves already observed in other countries, including Italy, Spain, France, and Germany [1]. The same data suggests that the number of infected will be in the order of dozens of thousands within a few days. Under unconstrained growth, this outbreak will affect millions of people in the next few weeks. This will most probably put the NHS at serious risk of not being able to cope with the flow of patients needing intensive care, as the number of ICU beds in the UK is not larger than that available in other neighbouring countries with a similar population [2]. Going for \herd immunity" at this point does not seem a viable option, as this will put NHS at an even stronger level of stress, risking many more lives than necessary. By putting in place social distancing measures now, the growth can be slowed down dramatically, and thousands of lives can be spared. We consider the social distancing measures taken as of today as insufficient, and we believe that addi- tional and more restrictive measures should be taken immediately, as it is already happening in other countries across the world. -
A BOINC-Based Volunteer Computing Infrastructure for Physics Studies At
Open Eng. 2017; 7:379–393 Research article Javier Barranco, Yunhai Cai, David Cameron, Matthew Crouch, Riccardo De Maria, Laurence Field, Massimo Giovannozzi*, Pascal Hermes, Nils Høimyr, Dobrin Kaltchev, Nikos Karastathis, Cinzia Luzzi, Ewen Maclean, Eric McIntosh, Alessio Mereghetti, James Molson, Yuri Nosochkov, Tatiana Pieloni, Ivan D. Reid, Lenny Rivkin, Ben Segal, Kyrre Sjobak, Peter Skands, Claudia Tambasco, Frederik Van der Veken, and Igor Zacharov LHC@Home: a BOINC-based volunteer computing infrastructure for physics studies at CERN https://doi.org/10.1515/eng-2017-0042 Received October 6, 2017; accepted November 28, 2017 1 Introduction Abstract: The LHC@Home BOINC project has provided This paper addresses the use of volunteer computing at computing capacity for numerical simulations to re- CERN, and its integration with Grid infrastructure and ap- searchers at CERN since 2004, and has since 2011 been plications in High Energy Physics (HEP). The motivation expanded with a wider range of applications. The tradi- for bringing LHC computing under the Berkeley Open In- tional CERN accelerator physics simulation code SixTrack frastructure for Network Computing (BOINC) [1] is that enjoys continuing volunteers support, and thanks to vir- available computing resources at CERN and in the HEP tualisation a number of applications from the LHC ex- community are not sucient to cover the needs for nu- periment collaborations and particle theory groups have merical simulation capacity. Today, active BOINC projects joined the consolidated LHC@Home BOINC project. This together harness about 7.5 Petaops of computing power, paper addresses the challenges related to traditional and covering a wide range of physical application, and also virtualized applications in the BOINC environment, and particle physics communities can benet from these re- how volunteer computing has been integrated into the sources of donated simulation capacity.