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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

CMS Collaboration; Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Brondolin, E.; Dragicevic, M.; Erö, J.; Flechl, M.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hartl, C.; Hörmann, N.; Hrubec, J.; Jeitler, M.; König, A.; Krätschmer, I.; ... mehr

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 √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 κtug and κtcg, the 95% CL upper limits on coupling strengths are |κtug|/Λ < 4.1 × 10− 3 TeV−1 and |κtcg|/Λ < 1.8 × 10− 2 TeV−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, res ... mehr


Zugehörige Institution(en) am KIT Institut für Experimentelle Kernphysik (IEKP)
Publikationstyp Zeitschriftenaufsatz
Jahr 2017
Sprache Englisch
Identifikator DOI: 10.1007/JHEP02(2017)028
ISSN: 1029-8479, 1126-6708
KITopen ID: 1000068579
Erschienen in Journal of high energy physics
Band 2017
Heft 2
Seiten 28
Lizenz CC BY-SA 4.0: Creative Commons Namensnennung – Weitergabe unter gleichen Bedingungen 4.0 International
Bemerkung zur Veröffentlichung Gefördert durch SCOAP3
Schlagworte Flavour Changing Neutral Currents, Hadron-Hadron scattering (experiments), Top physics
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