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
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 int...
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English English |
| Published: |
Springer Nature
2017
|
| Subjects: | |
| Online Access: | http://irep.iium.edu.my/63059/ http://irep.iium.edu.my/63059/ http://irep.iium.edu.my/63059/ http://irep.iium.edu.my/63059/1/63059_Search%20for%20anomalous%20Wtb%20couplings%20_article.pdf http://irep.iium.edu.my/63059/2/63059_Search%20for%20anomalous%20Wtb%20couplings%20_scopus.pdf |
| Summary: | 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 righthanded
tensor Wtb couplings are measured to be |f
R
V
| < 0.16, |f
L
T
| < 0.057, and −0.049 <
f
R
T < 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. |
|---|