Étude du potentiel de découverte du boson de Higgs produit par fusion de bosons vectoriels qq a qq H par le détecteur ATLAS au LHC

At the LHC, the vector boson fusion production mode will have a major im- pact on the Standard Model Higgs searches. The characteristic signature of two addition al jets in the forward regions of the detector and the low hadronic activity in the central part allows for a powerful rejection of background processes. This process is also the unique way for detecting H -t 7+7- decay mode. The work presented in this thesis shows the prospect for a Higgs boson, with H -t 7+ 7- and 100 < MH < 150 GeV jc 2 , discovery in ATLAS using vector boson fusion. In addi- tion, the production of the dominant background pro cess pp -t Z + 2 jets is studied using several theoretical approaches. Finally, The ATLAS Forward Calorimeter will have a major role in detecting and reconstructing the forward jets associated with the Higgs boson. A comparison with a GEANT4-based Monte Carlo simulation and test beam data of a prototype of the forward calorimeter has allowed a good description of the experimental data and a good understanding of its performances as weIl. Such comparison has also shown that GEANT4 is a very good tool for Monte Carlo simulations of LHC detectors.