Study of direct photon plus jet production in CMS experiment at $\sqrt{s}$ = 14 TeV

We present simulation results of $\gamma$ + Jet analysis using CMS (Compact Muon Solenoid) Object-Oriented software at the LHC center of mass energy ($\sqrt{s}$=14 TeV). The study of direct photon production helps in validating the perturbative quantum chromodynamics (pQCD) and constraining the gluon distribution of nucleons. Direct photon processes also represent a major contribution in estimating background to other Standard Model (SM) processes and signals of new physics. Thus these processes need to be understood precisely in the new energy regime mentioned above. In this work, we have done a detailed study of the complete GEANT4 simulated events of $\gamma$ + jet generated with Pythia and the related background processes at $\sqrt{s}$=14 TeV. Isolation cuts have been defined for the direct photon which improves the signal to background ratio by $\sim25%$ as compared to previous studies done in CMS. The inclusion of a $\Delta\phi$ cut at $40^0$ in the analysis leads to a further increase of $\sim15-17%$, thus giving an overall gain of $\sim42%$ in S/B ratio.We present simulation results of $\gamma$ + Jet analysis using CMS (Compact Muon Solenoid) Object-Oriented software at the LHC center of mass energy ($\sqrt{s}$=14 TeV). The study of direct photon production helps in validating the perturbative quantum chromodynamics (pQCD) and constraining the gluon distribution of nucleons. Direct photon processes also represent a major contribution in estimating background to other Standard Model (SM) processes and signals of new physics. Thus these processes need to be understood precisely in the new energy regime mentioned above. In this work, we have done a detailed study of the complete GEANT4 simulated events of $\gamma$ + jet generated with Pythia and the related background processes at $\sqrt{s}$=14 TeV. Isolation cuts have been defined for the direct photon which improves the signal to background ratio by $\sim25%$ as compared to previous studies done in CMS. The inclusion of a $\Delta\phi$ cut at $40^0$ in the analysis leads to a further increase of $\sim15-17%$, thus giving an overall gain of $\sim42%$ in S/B ratio.We present simulation results of gamma+jet analysis using CMS (compact muon solenoid) object-oriented software at the large hadron collider (LHC) center of mass energy = 14 TeV. The study of direct photon production helps in validating the perturb ative quantum chromodynamics (pQCD) and providing information on the gluon distribution in the nucleons. Direct photon processes also constitute a major background to several other standard model (SM) processes and signals of new physics. Thus these proce sses need to be understood precisely in the new energy regime. In this work, we have done a detailed study of the GEANT4 simulated gamma+jet events generated with Pythia, and the related background processes. Isolation cuts have been optimized for direct photon which improves the signal over background ratio by similar 25% as compared to previous studies done in CMS. The inclusion of a large Deltaphi cut between the photon and the leading jet at 40\textdegree in the analysis leads to a further increase o f similar 15% in S/B, thus giving an overall gain of similar 42% in S/B ratio