Search for the Standard Model Higgs boson in its associated production with a W vector boson in pp collisions at (s) = 1.96TeV
In this dissertation, results from a search for the Standard Model (SM) Higgs boson, at the DZERO experiment is shown. The SM is the theoretical framework which describes particles of matter and force carrier gauge bosons. To solve the mass problem in the SM, the Higgs mechanism was introduced. The Higgs mechanism causes an electroweak symmetry breaking and a new massive scalar boson was postulated. This particle is the Higgs boson. A search for the Higgs boson has been ongoing at the Tevatron where protons and antiprotons were allowed to collide at a center-of-mass energy of 1.96 TeV. For a low mass Higgs that is lower than 135 GeV, the dominant decay mode is Higgs to a pair of b-quarks. Work in this dissertation concentrated on a Higgs in the mass range of 100 - 150 GeV, where a W vector boson is produced in association with the Higgs boson. The final state chosen is one which contains a lepton (electron or a muon) a neutrino and a pair of b-quarks. This study used data provided by the DZERO experiment and computing resources provided by Fermilab. Results presented here are the outcome of analyzing 5.3 inverse-fb of data from RunII period. The analysis used different techniques to increase the sensitivity of the study. Data were subdivided based on lepton flavor, number of jets in sample, jets identified as b -jets and dates of collected data. A multivariate analysis technique based on boosted decision trees were used to separate signal from background processes, physical and instrumental. A good agreement between data and simulated events was observed. An observed (expected) upper limit of 4.5 (4.8) for a Higgs of mass 115 GeV was set on the ratio of the Higgs production to its decay branching ratio at the 95% confidence level.
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- Physics, Elementary Particles and High Energy;Physics, Theory;Physics, Electricity and Magnetism;Physics, Astronomy and Astrophysics