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

• Main Authors: Apyan, Aram (Contributor), Barbieri, Richard Alexander (Contributor), Baty, Austin Alan (Contributor), Bierwagen, Katharina (Contributor), Brandt, Stephanie Akemi (Contributor), Busza, Wit (Contributor), Cali, Ivan Amos (Contributor), Di Matteo, Leonardo (Contributor), Gomez-Ceballos, Guillelmo (Contributor), Goncharov, Maxim (Contributor), Gulhan, Doga Can (Contributor), Klute, Markus (Contributor), Lai, Yue Shi (Contributor), Lee, Yen-Jie (Contributor), Levin, Andrew Michael (Contributor), Luckey, P. David, Jr (Contributor), Paus, Christoph M. E. (Contributor), Ralph, Duncan Kelley (Contributor), Roland, Christof E. (Contributor), Roland, Gunther M. (Contributor), Stephans, George S. F. (Contributor), Sumorok, Konstanty C. (Contributor), Velicanu, Dragos Alexandru (Contributor), Veverka, Jan (Contributor), Wyslouch, Boleslaw (Contributor), Yang, Mingming (Contributor), Zanetti, Marco (Contributor), Zhukova, Victoria (Contributor)
• Other Authors: Massachusetts Institute of Technology. Department of Physics (Contributor), Massachusetts Institute of Technology. Laboratory for Nuclear Science (Contributor), Massachusetts Institute of Technology. School of Science (Contributor)
• Format: Article
• Language: English
• Published: Springer-Verlag, 2015-08-26T18:07:20Z.
• Subjects: Article
• Online Access: Get fulltext

 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[superscript -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[bar over t] + 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, μ, 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 μ < 4.2 (3.3), corresponding to a best fit value [^ over μ] = 1.2[+1.6 over −1.5].