SUSY search at CMS in met plus jets topologies at S=14 TeV and response comparison of the CMS calorimeters to pions between Monte Carlo and test beam

Standard Model (SM) of Particle Physics has some shortcomings. Supersymmetry,(SUSY) is one of the newest and robust models to overcome shortcomings of the SM.SUSY which introduces a super partner to each of the SM particles explains problemsof SM. However, these super partner particles have not been detected yet by the particledetectors in the experiments. Therefore, SUSY must be a broken symmetry and it needsto be tested by the experiments. Compact Muon Solenoid (CMS) experiment of the LargeHadron Collider (LHC) will try to detect the SUSY particles that might be seen in highenergy scale such as 1 TeV or more. In this thesis, one of the SUSY search channels,multijets plus missing transverse energy (MET) is explained. Multijets are generated atthe end of the hadronic decays and MET is coming from particles which are very weaklyinteracting with the detector materials such as neutrino and muon. While testing theSUSY theory, we must have enough information about the detector behavior in order todistinguish the signal sources. To understand the detector response, Test Beam (TB) of2006 results and Monte Carlo studies were compared. ECAL plus HCAL calorimeterenergy responses were compared to single particles between Monte-Carlo (MC) and TB.Single pion particles were used for this study in different beam energy ranges for TB andMC.