Research Information System
Thesis Type: Doctorate
Institution Of The Thesis: Orta Doğu Teknik Üniversitesi, Faculty of Arts and Sciences, Department of Physics, Turkey
Approval Date: 2002
Student: HATİCE DURAN (YILDIZ)
Supervisor: MEHMET TEVFİK ZEYREK
Abstract:The experimental observation of Higgs boson will be fundamental for a better understanding of the electroweak symmetry breaking mechanism. In this thesis the Standard Model Higgs boson decaying to a WW or ZZ pair in the weak boson fusion channel is studied for the LHC CMS experiment at CERN. This study utilizes the PYTHIA Monte Carlo event generator and the CMS detector simulation (CMS JET). Throughout this work, the observability of Higgs signal in the wide mass range is explored through WW -> lujj, ZZ ->? lljj and ZZ -> llvv final states. In the analysis scheme the weak bosons from their decay products are first reconstructed which are then combined to look at the Higgs signal. The differences in the kinematics and the characteristics of Higgs production with forward jets in the weak boson fusion process are used to optimize the signal over background ratio. It is shown that the forward jet tagging together with the central jet veto reduces the large QCD W/Z + jets and the top backgrounds enormously. uiThe significant signals are obtained for H ->? WW and H -* ZZ. In the H -»? WW -¥ Ivjj and H - ». ZZ -» JZjj channels the Higgs signal is clearly seen with a good mass peak. In the H - >? ZZ -> Wi/v channel no mass peak can be recontructed, but the signal can be detected in the missing Et spectrum. The required luminosity for the observation of the Higgs boson within the mass range of 300-800 GeV is shown to be 10 to 20 fb~l with a signal significance of five standard deviation