${\mathit {\mathit t}}$-quark EW Couplings

${{\mathit W}}$ helicity fractions in top decays. ${{\mathit F}_{{{0}}}}$ is the fraction of longitudinal and ${{\mathit F}_{{{+}}}}$ the fraction of right-handed ${{\mathit W}}$ bosons. ${{\mathit F}_{{{{V+A}}}}}$ is the fraction of $\mathit V+\mathit A$ current in top decays. The effective Lagrangian (cited by ABAZOV 2008AI) has terms f${}^{L}_{1}$ and f${}^{R}_{1}$ for $\mathit V−\mathit A$ and $\mathit V+\mathit A$ couplings, f${}^{L}_{2}$ and f${}^{R}_{2}$ for tensor couplings with b$_{R}$ and b$_{L}$ respectively.

${{\mathit F}_{{{-}}}}$

INSPIRE   JSON  (beta) PDGID:
Q007TVN
VALUE CL% DOCUMENT ID TECN  COMMENT
$\bf{ 0.315 \pm0.010}$ OUR AVERAGE
$0.315$ $\pm0.006$ $\pm0.009$ 1
AAD
2020Y
 LHC ATLAS+CMS combined
$0.310$ $\pm0.022$ $\pm0.022$ 2
CHATRCHYAN
2013BH
 CMS ${{\mathit F}_{{{-}}}}$ = B(${{\mathit t}}$ $\rightarrow$ ${{\mathit W}_{{{-}}}}{{\mathit b}}$)
$0.32$ $\pm0.04$ 3
AAD
2012BG
 ATLS ${{\mathit F}_{{{-}}}}$ = B(${{\mathit t}}$ $\rightarrow$ ${{\mathit W}_{{{-}}}}{{\mathit b}}$)
• • We do not use the following data for averages, fits, limits, etc. • •
$> 0.264 \pm0.044$ 95 4
AABOUD
2017BB
 ATLS ${{\mathit F}_{{{-}}}}$ = ${{\mathit f}_{{{1}}}}$(1 $−$ ${{\mathit f}_{{{1}}}^{+}}$), Repl. by AAD 2020Y
$0.323$ $\pm0.008$ $\pm0.014$ 5
KHACHATRYAN
2016BU
 CMS ${{\mathit F}_{{{-}}}}$ = B(${{\mathit t}}$ $\rightarrow$ ${{\mathit W}_{{{-}}}}{{\mathit b}}$), Repl. by AAD 2020Y
1  AAD 2020Y based on about 20 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 8 TeV for each experiment. The first error stands for the sum of the statistical and background uncertainties, and the second error for the remaining systematic uncertainties. The measurements used events with one lepton and different jet multiplicities in the final state. The result is consistent with the NNLO SM prediction of $0.311$ $\pm0.005$ for ${\mathit m}_{{{\mathit t}}}$ = $172.8$ $\pm1.3$ GeV.
2  Based on 5.0 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 7 TeV. CHATRCHYAN 2013BH studied events with large $\not E_T$ and ${{\mathit \ell}}$ +${}\geq{}$4 jets using a constrained kinematic fit.
3  Based on 1.04 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 7 TeV. AAD 2012BG studied events with large $\not E_T$ and either ${{\mathit \ell}}$ +${}\geq{}$4j or ${{\mathit \ell}}{{\mathit \ell}}$ +${}\geq{}$2j. The uncertainties are not independent, $\rho ({{\mathit F}_{{{0}}}},{{\mathit F}_{{{-}}}}$) = $-0.96$.
4  AABOUD 2017BB based on 20.2 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 8 TeV. Triple-differential decay rate of top quark in the ${{\mathit t}}$-channel single-top production is used to simultaneously determine five generalized ${{\mathit W}}{{\mathit t}}{{\mathit b}}$ couplings as well as the top polarization. No assumption is made for the other couplings. The authors reported ${{\mathit f}_{{{1}}}}$ = $0.30$ $\pm0.05$ and ${{\mathit f}_{{{1}}}^{+}}$ $<$ $0.120$ which we converted to ${{\mathit F}_{{{-}}}}$ = ${{\mathit f}_{{{1}}}}(1$ $−$ ${{\mathit f}_{{{1}}}^{+}}$). See this paper for constraints on other couplings not included here.
5  KHACHATRYAN 2016BU based on 19.8 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 8 TeV using ${{\mathit t}}{{\overline{\mathit t}}}$ events with ${{\mathit \ell}}$ + $\not E_T$ + ${}\geq{}$4 jets(${}\geq{}$2 ${{\mathit b}}$). The errors of ${{\mathit F}_{{{0}}}}$ and ${{\mathit F}_{{{-}}}}$ are correlated with a correlation coefficient $\rho ({{\mathit F}_{{{0}}}}$, ${{\mathit F}_{{{-}}}}$) = $-0.87$. The result is consistent with the NNLO SM prediction of $0.311$ $\pm0.005$ for ${\mathit m}_{{{\mathit t}}}$ = $172.8$ $\pm1.3$ GeV.
References