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).

Khachatryan, V., Sirunyan, A.M., Tumasyan, A., Adam, W., Bergauer, T., Dragicevic, M., et al. (2015). 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. THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS, 75(6) [10.1140/epjc/s10052-015-3454-1].

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

ANDROSOV, KONSTANTIN;GRIPPO, MARIA TERESA;SQUILLACIOTI, PAOLA;
2015-01-01

Abstract

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).
2015
Khachatryan, V., Sirunyan, A.M., Tumasyan, A., Adam, W., Bergauer, T., Dragicevic, M., et al. (2015). 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. THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS, 75(6) [10.1140/epjc/s10052-015-3454-1].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11365/978937