Naslov
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

Autori
Khachatryan, Vardan ; ... ; Morović, Srećko ; Ferenček, Dinko ; Đurić, Senka ; Godinović, Nikola ; Lelas, Damir ; Polić, Dunja ; Puljak, Ivica ; Antunović, Željko ; Kovač, Marko ; Brigljević, Vuko ; Kadija, Krešo ; Luetić, Jelena ; Mekterović, Darko ; Sudić, Lucija ; ... ; Woods, Nate

Izvornik
European physical journal C : particles and fields (1434-6044) 75 (2015), 6; 251-1

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
High energy physics ; Experimental particle physics ; LHC ; CMS ; Standard Model

Sažetak
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 inverse femtobarns 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-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-hat = 1.2 +1.6 -1.5.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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