A Search for the Higgs Boson in the $ZH$ Dilepton Decay Channel at CDF II

[摘要] This dissertation describes a search for the Standard Model Higgs boson produced in association with the Z boson via Higgs-strahlung at the CDF II detector at the Tevatron. At a Higgs boson mass between 100 GeV/c{sup 2} and 135 GeV/c{sup 2}, the primary Higgs decay mode is to a pair of b quarks. The associated Z boson can decay to a pair of electrons or muons, allowing detection of a final event signature of two visible leptons and two b quarks. This final state allows reduction of large QCD backgrounds compared to a hadronic Z boson decay, leading to a more sensitive search. To increase sensitivity, standard model matrix element probabilities for ZH signal and the dominant backgrounds are used as components to a likelihood fit in signal fraction. In 2.7 fb{sup -1} of CDF II data, we see no evidence of production of a Higgs boson with a mass between 100 GeV c{sup 2} and 150 GeV/c{sup 2}. Using the Feldman-Cousins technique to set a limit, at 95% coverage and a Higgs boson mass of 115 GeV/c{sup 2}, the median expected limit was 12.1 x {sigma}{sub SM} and a limit of 8.2 x {sigma}{sub SM} was observed, where {sigma}{sub SM} is the NNLO theoretical cross section of p{bar p} {yields}ZH {yields} l +l -b{bar b} at {radical}s=1.96 TeV . Cross section limits are computed at a range of Higgs boson mass values between 100 GeV/c {sup 2} and 150 GeV/c{sup 2}.

[发布日期] 2009-07-01

[学科分类] 物理（综合）

[关键词] B QUARKS;BOSONS;CROSS SECTIONS;DATA;DECAY;DETECTION;ELECTRONS;FERMILAB COLLIDER DETECTOR;FERMILAB TEVATRON;HIGGS BOSONS;LEPTONS;MASS;MATRIX ELEMENTS;MUONS;PRODUCTION;QUANTUM CHROMODYNAMICS;RANGE;REDUCTION;SENSITIVITY;SIGNALS;STANDARD MODEL;YIELDS Experiment-HEP