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

outside the neutral kaon system. The significanceof Belle was recognized by the 2008 Nobel Prizefor Physics, awarded to Nambu, Kobayashi andMaskawa for “the discovery of the origin of thebroken symmetry which predicts the existenceof at least three families of quarks in nature”. Thecitation prominently highlights the results of Belle.The EPP group has played a major role in the Bellecollaboration and has significantly contributed to thesuccess of this experiment.Over the past year the KEKB accelerator hascontinuously improved the performance of the “crabcavities” which rotate beam bunches to allow themto interact and collide head-on. A number of keyparameters have been identified which have limitedthe performance of the cavities were been identifiedand fixed. As a result the KEKB accelerator achieveda new world-record Luminosity of 2.1x10 34 cm 2 sec -1 .This value is some 20% higher than the previousworld record, also set by KEKB, even though thenew beam currents employed were substantiallysmaller than previously used. Also in 2009, Belleannounced the result of a number of measurementswhich are 1-2.8 sigma away from expectations of theStandard Model. We will need a substantial increasein data to determine if these results are the effect of“New Physics” or simply statistical fluctuations.In 2009 KEK received preliminary approval for anupgrade of the KEKB accelerator which is planned toincrease the luminosity by approximately a factor of50. Construction of the new facility will commencein 2010. At the same time Belle members haveformed the Belle II collaboration to design and builda detector to exploit this increase of luminosity.The increase in luminosity will enable the Belle IIexperiment to perform precision measurementswhere the effects of Physics beyond the StandardModel of Particle Physics will be manifest.Consequently Belle II will search for “New Physics”in a way complementary to that of ATLAS.This year Antonio Limosani, Phillip Urquijo andRobin Wedd submitted papers to refereed Journalsdescribing their measurements of the branchingratios for B→X sγ, B→X ul and B→Kη’γ respectively.Both Antonio Limonsani and Phillip Urquijo’s paperswere submitted to the prestigious Journal PhysicsReview Letters.Finally, Craig Everton was awarded his Ph.D. onthe topic “Measurements of various B → D shhdecays” and Robin Wedd submitted in Ph.D. thesis,“Measurement of the branch ratio for B→Kη’γ” .Both these are based on Belle data.Distributed Computing.Martin Sevior and Tom Fifield, made the first detailedinvestigations of Cloud Computing for High EnergyPhysics. These investigations were presented atthe Computing in High Energy and Nuclear Physics2009 conference in Prague, the InternationalSymposium on Grid Computing, in Taipei and at aspecial Colloquium at the Victorian Partnership forAdvanced Computing. Our results were also heavilycited by Neil Geddes in his talk “Future Perspectivesof Computing in HEP” at the premiere conferencein High Energy Physics for 2009, InternationalSymposia on Lepton and Photon Interactions atHigh Energies in Hamburg, Germany. In this workwe showed how the versatile commercial ElasticComputing Cloud (EC2) of the Amazon.comcompany can be used to supplement the computingresources of High Energy Physics experiments.Advanced Accelerator andInstrumentation GroupThe Australian group makes significant contributionsto Belle through data analysis and DistributedComputing. Tom Fifield joined the Belle and BelleII projects this year as a Software Engineer. MartinSevior leads the Belle II Distributed Computinggroup.Roger Rassool leads this group’s research intothe development of advanced accelerators andinstrumentation. The group has continued to developits collaboration, both locally and internationally.In particular, the collaboration at the Paul-SchiererInsitut has developed considerably with theinstallation of the Pilatus 1M detector at theAustralian Synchrotron. This detector is based on anovel photon counting approach, pioneered by thewww.physics.unimelb.edu.auSLS-Detector group for use in the CMS experiment.31