Annual Report 2009.pdf - School of Physics - University of Melbourne

group reports & publicationsexperimental particle physics (EPP)A/Prof Martin SeviorThe academics of the EPP group are ElisabettaBarberio, Roger Rassool, Geoff Taylor and myself.Our activities span Experimental Particle Physics,detector development, accelerator physicsresearch and computing grid development. Thecornerstones of our research are the ATLAS andBelle experiments at CERN in Switzerland and KEKin Japan respectively. In addition Dr. Rassool leadsa very active group developing advanced particledetectors and innovations in accelerator physics.We are ably supported by Drs Antonio Limosani andUli Felzmann as Research Associates. Tim Dycesupports our Tier 2 Grid Facility. In 2009 Tom Fifield,a software engineer, joined us in the role of griddeveloper.ATLASThe intense world-wide interest in the Scientificprogram at the Large Hadron Collider and the ATLASexperiment was manifest when in September 10 th2008, over a billion people world-wide watched theturn-on of the Large Hadron Collider (LHC). It wasa media event of the significance of the first manstepping on the moon. From the expected search forthe “God Particle” to fears of the end of the world,people across the globe were fixated by the start ofthis incredible scientific instrument.On 19 September 2008 one sector of the LargeHadron Collider warmed above superconductingtemperature leading to the release of helium gas intothe tunnel. The incident was due to a faulty electricalconnection between two magnets.An intense program to repair the damage and torefit further safety measures and control systemsfor the LHC commenced and was completed.The beam was restarted in December 2009. Datafrom collisions were almost immediately recordedand whisked around the Earth via the World LargeHadron Collider data Grid (WLCG). In additionto many other locations, these data were madeavailable to our Tier 2 facility in Melbourne whereEPP students contributed to the first data analysisand detector validation efforts. This ability torapidly distribute data throughout the whole ATLAScollaboration was a marvelous validation of thedecade-long effort to develop data grid technology.30This allows clusters of computers to be tightlyintegrated and allows the rapid sharing of data tomembers of a grid-enabled collaboration. In thecase of ATLAS this is some 2000 Physics locatedall over the globe. The Melbourne Tier-2 facility isfully integrated into this network and is the onlyinternationally connected grid site in Australia.The implications of the ATLAS experiment areenormous with the possibility of the discoveryof new particles and physics beyond the standardmodel of our understanding. One of the main goalsremains the unearthing of the Higgs Boson, thequantum of the postulated all pervasive Higgs Fieldwhich is assumed to give all particles their mass.Although it will be quite some time before themachine and its ensuing data have been refinedsufficiently to be able to identify the signatures ofthese Higgs particles, either way its discovery ornon-discovery will be momentous. If it is seen, it willbe a triumph for a theory that has given the answerto the very basic question “Why are some particlesmore massive than others?. If it is not seen it will beback to the drawing board as physicists grapple withthe most fundamental questions in our Universe.Either way, it is certain that both ATLAS and itscompetitor CMS will be adding to the scientific textbooks of the future. We are eagerly looking forwardto the ramp up of the experiment expected in 2010and to start the search for “New Physics” in earnest.The EPP group is heavily involved in analysis ofATLAS data. Through the leadership of ElisabettaBarberio and Geoff Taylor, we play a major role inthe analysis of ATLAS data through our work in thedilepton and tau reconstruction groups.In 2009 Antonio Limonsani won an ARC AustralianPostdoctoral Fellowship for his proposal : “Searchingfor Supersymmetry in the Universe with the ATLASexperiment at the Large Hadron Collider”. He iscurrently working as inner detector software releasecoordinator for the ATLAS experiment.BelleBelle is the experiment at the KEK asymmetricelectron-positron accelerator which provides theworld highest luminosity collider and makes copiousnumbers of B-mesons. Belle has made numerousdiscoveries since it commenced data collectionin 1999, including the observation of CP violationin B-meson decays, the first such measurementwww.physics.unimelb.edu.au