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

Date

2017-02-07

Authors

The, C. M. S. collaboration
Khachatryan, V.
Sirunyan, A. M.
Tumasyan, A.
Adam, W.
Asilar, E.
Bergauer, T.
Brandstetter, J.
Brondolin, E.
Dragicevic, M.

Journal Title

Journal ISSN

Volume Title

Publisher

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 s=7 and 8 TeV correspond to integrated luminosities of 5.0 and 19.7 fb?1, 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 |fV R| < 0.16,?|fT L| < 0.057, and ? 0.049 < fT R < 0.048, respectively. For the FCNC couplings ?tug and ?tcg, the 95% CL upper limits on coupling strengths are |?tug|/? < 4.1 × 10? 3 TeV?1 and |?tcg|/? < 1.8 × 10? 2 TeV?1, where ? is the scale for new physics, and correspond to upper limits on the branching fractions of 2.0 × 10?5 and 4.1 × 10?4 for the decays t ? ug and t ? cg, respectively.[Figure not available: see fulltext.] © 2017, The Author(s).

Description

Citation: The, C. M. S. c., Khachatryan, V., Sirunyan, A. M., Tumasyan, A., Adam, W., Asilar, E., . . . Woods, N. (2017). Search for anomalous Wtb couplings and flavour-changing neutral currents in t-channel single top quark production in pp collisions at ?s=7 and 8 TeV. Journal of High Energy Physics, 2017(2). doi:10.1007/JHEP02(2017)028

Keywords

Flavour Changing Neutral Currents, Hadron-Hadron Scattering (Experiments), Top Physics

Citation