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

The CMS collaboration

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19 Citations (Scopus)

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 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, respectively.[Figure not available: see fulltext.]

Original languageEnglish
Article number28
JournalJournal of High Energy Physics
Volume2017
Issue number2
DOIs
Publication statusPublished - 1 Feb 2017

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neutral currents
quarks
collisions
confidence
protons
exclusion
muons
luminosity
tensors
physics
detectors
decay
predictions
interactions

Keywords

  • Flavour Changing Neutral Currents
  • Hadron-Hadron scattering (experiments)
  • Top physics

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

Cite this

@article{4de138d19ef04c4aab8902f96c9ab6db,
title = "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",
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 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, respectively.[Figure not available: see fulltext.]",
keywords = "Flavour Changing Neutral Currents, Hadron-Hadron scattering (experiments), Top physics",
author = "{The CMS collaboration} and V. Khachatryan and Sirunyan, {A. M.} and A. Tumasyan and W. Adam and E. Asilar and T. Bergauer and J. Brandstetter and E. Brondolin and M. Dragicevic and J. Er{\"o} and M. Flechl and M. Friedl and R. Fr{\"u}hwirth and Ghete, {V. M.} and C. Hartl and N. H{\"o}rmann and J. Hrubec and M. Jeitler and A. K{\"o}nig and I. Kr{\"a}tschmer and D. Liko and T. Matsushita and I. Mikulec and D. Rabady and N. Rad and B. Rahbaran and H. Rohringer and J. Schieck and J. Strauss and W. Treberer-Treberspurg and W. Waltenberger and Wulz, {C. E.} and V. Mossolov and N. Shumeiko and {Suarez Gonzalez}, J. and S. Alderweireldt and {De Wolf}, {E. A.} and X. Janssen and J. Lauwers and {Van De Klundert}, M. and {Van Haevermaet}, H. and {Van Mechelen}, P. and {Van Remortel}, N. and {Van Spilbeeck}, A. and {Abu Zeid}, S. and F. Blekman and J. D’Hondt and N. Daci and {De Bruyn}, I. and Othmane Bouhali",
year = "2017",
month = "2",
day = "1",
doi = "10.1007/JHEP02(2017)028",
language = "English",
volume = "2017",
journal = "Journal of High Energy Physics",
issn = "1126-6708",
publisher = "Springer Verlag",
number = "2",

}

TY - JOUR

T1 - 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

AU - The CMS collaboration

AU - Khachatryan, V.

AU - Sirunyan, A. M.

AU - Tumasyan, A.

AU - Adam, W.

AU - Asilar, E.

AU - Bergauer, T.

AU - Brandstetter, J.

AU - Brondolin, E.

AU - Dragicevic, M.

AU - Erö, J.

AU - Flechl, M.

AU - Friedl, M.

AU - Frühwirth, R.

AU - Ghete, V. M.

AU - Hartl, C.

AU - Hörmann, N.

AU - Hrubec, J.

AU - Jeitler, M.

AU - König, A.

AU - Krätschmer, I.

AU - Liko, D.

AU - Matsushita, T.

AU - Mikulec, I.

AU - Rabady, D.

AU - Rad, N.

AU - Rahbaran, B.

AU - Rohringer, H.

AU - Schieck, J.

AU - Strauss, J.

AU - Treberer-Treberspurg, W.

AU - Waltenberger, W.

AU - Wulz, C. E.

AU - Mossolov, V.

AU - Shumeiko, N.

AU - Suarez Gonzalez, J.

AU - Alderweireldt, S.

AU - De Wolf, E. A.

AU - Janssen, X.

AU - Lauwers, J.

AU - Van De Klundert, M.

AU - Van Haevermaet, H.

AU - Van Mechelen, P.

AU - Van Remortel, N.

AU - Van Spilbeeck, A.

AU - Abu Zeid, S.

AU - Blekman, F.

AU - D’Hondt, J.

AU - Daci, N.

AU - De Bruyn, I.

AU - Bouhali, Othmane

PY - 2017/2/1

Y1 - 2017/2/1

N2 - 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 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, respectively.[Figure not available: see fulltext.]

AB - 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 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, respectively.[Figure not available: see fulltext.]

KW - Flavour Changing Neutral Currents

KW - Hadron-Hadron scattering (experiments)

KW - Top physics

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U2 - 10.1007/JHEP02(2017)028

DO - 10.1007/JHEP02(2017)028

M3 - Article

AN - SCOPUS:85012230357

VL - 2017

JO - Journal of High Energy Physics

JF - Journal of High Energy Physics

SN - 1126-6708

IS - 2

M1 - 28

ER -