Search for the associated production of the Higgs boson with a top-quark pair

TL;DR

This paper reports a search for the Higgs boson produced alongside a top-quark pair, analyzing data from proton-proton collisions at 7 and 8 TeV, and measures the signal strength relative to the standard model.

Contribution

It provides the first combined analysis of multiple Higgs decay channels in t tbar H production at these energies.

Findings

Observed signal strength mu = 2.8 +/- 1.0

Evidence for t tbar H production with a significance approaching 3 sigma

Constraints on Higgs-top coupling consistent with the standard model

Abstract

A search for the standard model Higgs boson produced in association with a top-quark pair (t tbar H) is presented, using data samples corresponding to integrated luminosities of up to 5.1 inverse femtobarns and 19.7 inverse femtobarns collected in pp collisions at center-of-mass energies of 7 TeV and 8 TeV respectively. The search is based on the following signatures of the Higgs boson decay: H to hadrons, H to photons, and H to leptons. The results are characterized by an observed t tbar H signal strength relative to the standard model cross section, mu = sigma/sigma[SM], under the assumption that the Higgs boson decays as expected in the standard model. The best fit value is mu = 2.8 +/- 1.0 for a Higgs boson mass of 125.6 GeV.