Search for ttH production using the Matrix Element Method

Collaboration
2014
24 pages
Report number:
  • CMS-PAS-HIG-14-010
Experiments:

Citations per year

2014201520161293
Abstract:
A search for Standard Model ttˉH\mathrm{t\bar{t}H} production in the Hbb\mathrm{H\rightarrow b\overline{b} } final state is presented. The measurement of the ttˉH\mathrm{t\bar{t}H} process plays an important role in Higgs characterization studies since it provides a direct probe of the Higgs Yukawa coupling to fermions, particularly to the top quark. Events with one lepton and at least 5 jets or two leptons and at least 4 jets are selected from 19.519.5 fb1^{-1} of collision data collected by CMS at s=8\sqrt{s}=8 TeV. In order to separate the ttˉH\mathrm{t\bar{t}H} signal from the larger production of ttˉ+jets\mathrm{t\bar{t}+jets}, this analysis uses a Matrix Element Method that assigns a signal and background probability density to each event in terms of a particular Born-level amplitude. A likelihood ratio of these probability densities is used to extract the signal. The statistical interpretation is presented in the form of 95\% CL exclusion limits on the signal strength modifier μ=σ/σSM\mu=\sigma/\sigma_{\mathrm{SM}} and provides an expected (observed) exclusion limit of μ<2.9\mu<2.9 (3.33.3), corresponding to a best-fit value μ^=0.671.33+1.35\hat{\mu}=0.67^{+1.35}_{-1.33}.
Note:
  • Preliminary results
  • Data
  • top: pair production
  • coupling: Yukawa
  • background
  • CMS
  • p p: scattering
  • Higgs particle: associated production
  • Higgs particle: hadronic decay
  • bottom: pair production
  • statistical analysis