Search for a standard model Higgs boson produced in association with a top-quark pair and decaying to bottom quarks using a matrix element method


Khachatryan V., Sirunyan A. M., Tumasyan A., Adam W., Bergauer T., Dragicevic M., ...Daha Fazla

EUROPEAN PHYSICAL JOURNAL C, cilt.75, sa.6, 2015 (SCI-Expanded) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 75 Sayı: 6
  • Basım Tarihi: 2015
  • Doi Numarası: 10.1140/epjc/s10052-015-3454-1
  • Dergi Adı: EUROPEAN PHYSICAL JOURNAL C
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • İstanbul Üniversitesi Adresli: Hayır

Özet

A search for a standard model Higgs boson produced in association with a top-quark pair and decaying to bottom quarks is presented. Events with hadronic jets and one or two oppositely charged leptons are selected from a data sample corresponding to an integrated luminosity of 19.5 fb(-1) collected by the CMS experiment at the LHC in pp collisions at a centre-of-mass energy of 8 TeV. In order to separate the signal from the larger t (t) over bar + jets background, this analysis uses a matrix element method that assigns a probability density value to each reconstructed event under signal or background hypotheses. The ratio between the two values is used in a maximum likelihood fit to extract the signal yield. The results are presented in terms of the measured signal strength modifier, mu, relative to the standard model prediction for a Higgs boson mass of 125 GeV. The observed (expected) exclusion limit at a 95% confidence level is mu < 4.2 (3.3), corresponding to a best fit value <(mu)over cap> = 1.2(-1.5)(+1.6).