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
(2017) Journal of High Energy Physics — Vol. 1702, p. 28 (2017)
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- Authors
Wertz, Sébastien 
- et. al.
- 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 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.
- Affiliations
Citations
CMS, Bakhshiansohi, H., Beluffi, C., Bondu, O., Brochet, S., Bruno, G., Caudron, A., Ceard, L., de Visscher, S., Delaere, C., Delcourt, M., Forthomme, L., François, B., Giammanco, A., Jafari, A., Jez, P., Komm, M., Lemaitre, V., Magitteri, A., et al. (2017). 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. Journal of High Energy Physics, 1702, 28. https://doi.org/10.1007/JHEP02(2017)028 (Original work published 2017)