Header

UZH-Logo

Maintenance Infos

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


CMS Collaboration; Canelli, Florencia; Kilminster, Benjamin; Aarestad, Thea; Caminada, Lea; De Cosa, Annapaoloa; Del Burgo, Riccardo; Donato, Silvio; Galloni, Camilla; Hinzmann, Andreas; Hreus, Tomas; Ngadiuba, Jennifer; Pinna, Deborah; Rauco, Giorgia; Robmann, Peter; Salerno, Daniel; Schweiger, Korbinian; Seitz, Claudia; Takahashi, Yuta; Zucchetta, Alberto; 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, 02:028.

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 $fb^{−1}$, 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 |$f_{V}$$^{R}$| < 0.16, |$f_T$$^L$| < 0.057, and − 0.049 < $f_T$$^R$ < 0.048, respectively. For the FCNC couplings $κ_{tug}$ and $κ_{tcg}$, the 95% CL upper limits on coupling strengths are $|κ_{tug}|/Λ < 4.1 × 10^{−3} TeV^{−1}$ and $|κ_{tcg}|/Λ < 1.8 × 10^{−2} TeV^{−1}$, 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.

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 $fb^{−1}$, 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 |$f_{V}$$^{R}$| < 0.16, |$f_T$$^L$| < 0.057, and − 0.049 < $f_T$$^R$ < 0.048, respectively. For the FCNC couplings $κ_{tug}$ and $κ_{tcg}$, the 95% CL upper limits on coupling strengths are $|κ_{tug}|/Λ < 4.1 × 10^{−3} TeV^{−1}$ and $|κ_{tcg}|/Λ < 1.8 × 10^{−2} TeV^{−1}$, 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.

Statistics

Citations

Dimensions.ai Metrics
2 citations in Web of Science®
8 citations in Scopus®
Google Scholar™

Altmetrics

Downloads

7 downloads since deposited on 15 Dec 2017
7 downloads since 12 months
Detailed statistics

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Physics Institute
Dewey Decimal Classification:530 Physics
Language:English
Date:2017
Deposited On:15 Dec 2017 10:22
Last Modified:19 Feb 2018 08:53
Publisher:Springer
ISSN:1029-8479
OA Status:Gold
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.1007/JHEP02(2017)028

Download

Download PDF  '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'.
Preview
Content: Published Version
Filetype: PDF
Size: 1MB
View at publisher
Licence: Creative Commons: Attribution 4.0 International (CC BY 4.0)