CMS sensitivity to quark contact interactions with dijets and CMS hadron calorimeter response studies

ABSTRACTPhD. THESISCMS SENSITIVITY TO QUARK CONTACT INTERACTIONS WITH DIJETSAND CMS HADRON CALORIMETER RESPONSE STUDIESSelda ESENDEPARTMENT OF PHYSICSINSTITUTE OF NATURAL AND APPLIED SCIENCESCUKUROVA UNIVERSITYşSupervisor: Prof. Dr. Eda ESKUTşYear: 2006, Pages: 156Jury: Prof. Dr. Eda ESKUTşü üProf. Dr. Gü lsen ONENGUTuüProf. Dr. Ayse POLATOZşProf. Dr. Vebil YILDIRIMAssoc. Prof. Dr. Ali HAVAREThis thesis presents a simulation of a search for quark contact interactions at CMS,utilising proven methods of jet triggering and analysis from the Tevatron. A full triggertable for single jets is developed, including thresholds and prescales at L1 and HLT. Theevolution of the table with instantaneous luminosity is presented, and the rates expectedfrom the trigger are estimated. We present an analysis of the QCD dijet mass distributionthat would result from taking data with this trigger. The canonical model of a contactinteraction among left-handed composite quarks changes the dijet angular distribution athigh dijet mass. The dijet ratio variable introduced at the Tevatron is used as a simplemeasure of the angular distribution as a function of dijet mass. The contact interactionsignal and QCD background are estimated for the dijet ratio as a function of dijet mass.The χ2 between the background and the signal is estimated, including systematics, and isused to find CMS sensitivity to the contact interaction scale Λ+ .This thesis also presents 3 studies of the CMS Hadron Calorimeter. First a study ofthe phi gaps between modules in the barrel. Second a study of the response of the endcapto electrons and muons. Third a study of the weight factor for the hadron outer calorimeter.Key Words: CMS, HCAL, jet, quark, compositeness