Publication Date:
2015-06-09
Description:
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 \(\,\text {fb}^\text {-1}\) collected by the CMS experiment at the LHC in \(\mathrm {p}\mathrm {p}\) collisions at a centre-of-mass energy of 8 \(\,\hbox {TeV}\) . In order to separate the signal from the larger \(\hbox {t}\overline{\hbox {t}}\) + 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, \(\mu \) , relative to the standard model prediction for a Higgs boson mass of 125 \(\,\hbox {GeV}\) . The observed (expected) exclusion limit at a 95 % confidence level is \(\mu 〈4.2\) (3.3), corresponding to a best fit value \(\hat{\mu }=1.2^{+1.6}_{-1.5}\) .
Print ISSN:
1434-6044
Electronic ISSN:
1434-6052
Topics:
Physics
