Reconstruction of missing transverse energy and prospect of searching for Higgs boson produced via vector boson fusion in Compact Muon Solenoid experiment

We performed full detector simulation studies of missing transverse energy (Emiss T ) reconstruction and correction, and the prospects for searching for a low mass Higgs Boson (120 < mH < 250 GeV/c 2 ) produced via the vector boson fusion (VBF) process through the decay of H → W+W− → `νjj at Compact Muon Solenoid (CMS) experiment in Large Hadron Collider (LHC). We developed a new jet energy correction algorithm by parameterizing the jet energy distribution around the jet axis. The jet energy resolution is improved by calibrating the jet energy scale and by reducing the variance of the measurement error. Correction functions showed good performance in restoring the jet transverse momentum (pT) spectrum. The methods provide a good framework to study jet quantities and optimize jet reconstruction and correction techniques. We evaluated the performance of the CMS detector for measuring the Emiss T using QCD events. We also studied the contributions from detector resolution, minimum bias pileup, event topology, tower energy thresholds and the exclusion of the unclustered region in the calorimeter. We built a comprehensive strategy for the Emiss T correction for leptonic events. The performance as applied to t¯t and W+jets events showed improved the Emiss T resolution, the azimuthal (φ) resolution and average Emiss T scale. Correction techniques based on jet, lepton, calorimeter isolation, pileup, underlying effect, and tunings based on specific physics channels were developed and optimized. To fully exploit the correlation between the Emiss T and various physics final states, we developed a physics model of Emiss T by factorizing the jet system from related detector effects based on QCD di-jet events, and then extended this model to a general multiple jet system. We used the model to evaluate the jet energy calibration on Emiss T and the influence of various detector effects on the Emiss T . Our study provided a fundamental framework to systematically understand, analyze, and evaluate Emiss T related quantities. We performed a feasibility study on a direct Higgs mass (mH) reconstruction for the low mass region (120 < mH < 250 GeV/c 2 ) by explicitly reconstructing hadronic and leptonic W from the Higgs boson decay using `νjj final states. A large number of background processes were simulated and studied. Various techniques were developed (lepton isolation, forward jet tagging, central jet selection, hadronic and leptonic W reconstruction, and Emiss T selection) to increase the significance of the signal events. For an integrated luminosity of 30 fb−1 , a 5σ discovery for 160 < mH < 180 GeV/c 2 can be achieved. We developed experimental data analysis methods to identify the existence of Higgs boson without needing accurate knowledge of the selection efficiency. Two main systematic issues were discussed: jet energy scale and initial (final) state radiation. The feasibility of the reconstruction paves the way of the H → W+W− → `νjj as an effective channel for the Higgs boson search via VBF in the most interested region of 120 < mH < 220 GeV/c 2 , while this channel was mainly considered for high mass Higgs boson search before.