Searches for a High mass Higgs boson produced in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV

Abstract

In this Thesis the electro-weak spontaneous symmetry breaking of the Standard Model (SM) is studied by searching for the scalar Higgs particle in the proton antiproton collisions of the Tevatron collider, at the center of mass energy √s = 1.96 TeV. We report on the inclusive search for the Higgs boson decaying to two W bosons in the final state characterized by two charged leptons (e or μ) and two neutrinos. The analysis of 4.8 fb$^{-1}$ of data recorded by the Collider Detector at Fermilab (CDF) shows no evidence of its production. We set 95% Confidence Level upper limits on the production cross section as a function of the mass $m_H$ in the range 110 to 200 GeV/$c^2$. For $m_H$ = 165 GeV/$c^2$ the observed limit is 1.3 times the SM predicted cross section (σH); the expected limit, in absence of signal, is 1.2+0.6 -0.4σ(H). These limits are the most stringent ones set by a single experiment up to date, for $m_H$ > 130 GeV/c2.