Search for anomalous Wtb couplings and flavourchanging neutral currents in tchannel single top quark production in pp collisions at sqrt(s) = 7 and 8 TeV
Abstract
Single top quark events produced in the t channel are used to set limits on anomalous Wtb couplings and to search for top quark flavourchanging neutral current (FCNC) interactions. The data taken with the CMS detector at the LHC in protonproton 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 righthanded vector, and left and righthanded 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 < 4.1E3 TeV1 and kappa[tcg]/Lambda < 1.8E2 TeV1, where Lambda is the scale for new physics, and correspond to upper limits on the branching fractions of 2.0E5 and 4.1E4 for the decays t to ug and t to cg, respectively.
 Publication:

arXiv eprints
 Pub Date:
 October 2016
 arXiv:
 arXiv:1610.03545
 Bibcode:
 2016arXiv161003545C
 Keywords:

 High Energy Physics  Experiment
 EPrint:
 Replaced with the published version. Added the journal reference and DOI. All the figures and tables can be found at http://cmsresults.web.cern.ch/cmsresults/publicresults/publications/TOP14007/index.html