Search for susy in missing transverse energy plus multijet topologies at sqrt (s) = 14 TeV and geant4 simulation of the CMS hadronic forward calorimeter in the 2004 test beam

ABSTRACTPhD. THESISSEARCH FOR SUSY IN MISSING TRANSVERSE ENERGY PLUS MULTIJET√TOPOLOGIES AT s = 14 TEV AND GEANT4 SIMULATION OF THE CMSHADRONIC FORWARD CALORIMETER IN THE 2004 TEST BEAM˙Taylan YETKINDEPARTMENT OF PHYSICSINSTITUTE OF NATURAL AND APPLIED SCIENCESUNIVERSITY OF CUKUROVAüSupervisor: Prof. Dr. Gü lsen Onengü tu uYear: 2006, Pages: 169üJury: Prof. Dr. Gü lsen Onengü tu uüProf. Dr. Yasar OnelşProf. Dr. Durmus Ali DemirşProf. Dr. Eda EskutşAssist. Prof. Dr. Ali HavareThe Standard Model (SM) of the particles and forces in the nature is believed to beincomplete and a stepping stone towards new physics. Minimal Supergravity (mSUGRA)is one of the considered models beyond SM. An analysis study is performed for the dis-covery of mSUGRA by using multijets and missing transverse energy as signal topologyin the final state. Methods and tools for the analysis are introduced. It is shown thatthe discovery of SUSY, if exists, is not an issue because of the large cross-section, how-ever the methods and analysis tools are important. Hadronic Forward (HF) Calorimetersin Compact Muon Solenoid (CMS) Experiment are introduced to expand the pseudo-rapidity coverage up to |η| = 5. The HF calorimeters will help to increase forward jettagging and missing transverse energy measurements. A Geant4 simulation of the HFdetectors which were tested in 2004 at CERN is performed and the simulation results arecompared with the test beam data. The comparisons are made for signal, energy resolu-tion and linearity of HF. The results from Geant4 for the electromagnetic physics are invery good agreement with the test beam results. On the other hand, since hadronic physicsis very different from electromagnetic, there are some differentiation among the physicsmodels that were used in GEANT4 and only one of them represent the pion test beam datavery well. The GEANT4 study is used in CMS collaboration to update the response of HFin the official simulation tool of CMS detector (OSCAR, Object Oriented Simulation forCMS Analysis and Reconstruction, which is also based on Geant4).Key Words: CMS, mSUGRA, GEANT4, HF.II