Search for the Standard Model Higgs Boson in ZH µ + µ - bb Production at DO and Evidence for the H -> bb Decay at the Tevatron.

Abstract

A search for ZH->mumubb is presented, using a Run 2 dataset with an integrated luminosity of 9.7 fb-1 collected by the D0 detector. Selected events contain at least two reconstructed jets and a Z candidate reconstructed with two opposite-sign charged muons. Random forests of decision trees are trained to distinguish between signal and background events in two orthogonal b-tag samples. The ZH->mumubb analysis is then combined with ZH->eebb analysis. For the combined results of ZH->llbb, no Higgs signal is observed, limits are set on the ZH cross section times branching ratio for different Higgs masses, from 90 to 150 GeV. For a SM Higgs boson of mass 125 GeV, the observed cross section limit is 7.1 times the SM cross section with an expected sensitivity of 5.1 times the SM cross section. The result of ZH->llbb channel has been combined with searches in other Higgs decay channels at the Tevatron, which led to the first evidence of H->bb.