Naslov
Search for anomalous Wtb couplings and flavour-changing neutral currents in t-channel single top quark production in pp collisions at sqrt(s) = 7 and 8 TeV

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

Kolaboracija
CMS Collaboration

Izvornik
The Journal of high energy physics (1126-6708) 2017 (2017); 28, 45

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

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

Sažetak
Single top quark events produced in the t channel are used to set limits on anomalous Wtb couplings and to search for top quark flavour-changing neutral current (FCNC) interactions. The data taken with the CMS detector at the LHC in proton-proton collisions at sqrt(s) = 7 and 8 TeV correspond to integrated luminosities of 5.0 and 19.7 inverse femtobarns, respectively. The analysis is performed using events with one muon and two or three jets. A Bayesian neural network technique is used to discriminate between the signal and backgrounds, which are observed to be consistent with the standard model prediction. The 95% confidence level (CL) exclusion limits on anomalous right- handed vector, and left- and right-handed tensor Wtb couplings are measured to be |f[V]^R| < 0.16, |f[T]^L| < 0.057, and -0.049 < f[T]^R < 0.048, respectively. For the FCNC couplings kappa[tug] and kappa[tcg], the 95% CL upper limits on coupling strengths are |kappa[tug]|/Lambda < 4.1E-3 TeV-1 and |kappa[tcg]|/Lambda < 1.8E-2 TeV-1, where Lambda is the scale for new physics, and correspond to upper limits on the branching fractions of 2.0E-5 and 4.1E-4 for the decays t to ug and t to cg, respectively.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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