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
Author(s)
CMS Collaboration; Abercrombie, Daniel Robert; Allen, Brandon Leigh; Apyan, Aram; Barbieri, Richard Alexander; Baty, Austin Alan; Bi, Ran; Bierwagen, Katharina; Brandt, Stephanie Akemi; Busza, Wit; Cali, Ivan Amos; Demiragli, Zeynep; Di Matteo, Leonardo; Gomez-Ceballos, Guillelmo; Goncharov, Maxim; Hsu, Dylan George; Iiyama, Yutaro; Innocenti, Gian Michele; Klute, Markus; Kovalskyi, Dmytro; Krajczar, Krisztian F.; Lai, Yue Shi; Lee, Yen-Jie; Levin, Amy Elizabeth; Luckey Jr, P David; Marini, Andrea Carlo; McGinn, Christopher Francis; Mironov, Camelia Maria; Narayanan, Siddharth Madhavan; Niu, Xinmei; Paus, Christoph M. E.; Roland, Christof E; Roland, Gunther M; Salfeld-Nebgen, Jakob Maxillian Henry; Stephans, George S. F.; Sumorok, Konstanty C; Tatar, Kaya; Varma, Mukund Madhav; Velicanu, Dragos Alexandru; Veverka, Jan; Wang, Jing; Wang, Ta-Wei; Wyslouch, Boleslaw; Yang, Ming; Wyslouch, Victoria; ... Show more Show less
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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 |fVR| < 0.16, |fTL| < 0.057, and − 0.049 < fTR< 0.048, respectively. For the FCNC couplings κtugand κtcg, the 95% CL upper limits on coupling strengths are |κtug|/Λ < 4.1 × 10⁻³TeV⁻¹and |κtcg|/Λ < 1.8 × 10⁻²TeV⁻¹, where Λ 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. Keywords: Flavour Changing Neutral Currents; Hadron-Hadron scattering (experiments); Top physics
Date issued
2017-02Department
Massachusetts Institute of Technology. Department of Nuclear Science and Engineering; Massachusetts Institute of Technology. Department of Physics; Massachusetts Institute of Technology. Laboratory for Nuclear ScienceJournal
Journal of High Energy Physics
Publisher
Springer Nature
Citation
Khachatryan, V. et al. “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 (February 2017): 28 © 2017 The Author(s)
Version: Final published version
ISSN
1029-8479