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

A search for the standard model Higgs boson produced in association with a topquark pair (ttH) is presented, using data samples corresponding to integrated luminosities of up to 5.1 fb−1 and 19.7 fb−1 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→ hadrons, H→ photons, and H→ leptons. The results are characterized by an observed ttH signal strength relative to the standard model cross section, μ = σ/σSM, under the assumption that the Higgs boson decays as expected in the standard model. The best fit value is μ = 2.8± 1.0 for a Higgs boson mass of 125.6 GeV. Published in the Journal of High Energy Physics as doi:10.1007/JHEP09(2014)087. c © 2014 CERN for the benefit of the CMS Collaboration. CC-BY-3.0 license ∗See Appendix A for the list of collaboration members ar X iv :1 40 8. 16 82 v2 [ he pex ] 1 8 Se p 20 14