${\mathit {\mathit t}}$-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   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:
AAD 2020Y
JHEP 2008 051 Combination of the W boson polarization measurements in top quark decays using ATLAS and CMS data at $\sqrt{s} =$ 8 TeV
AABOUD 2017BB
JHEP 1712 017 Analysis of the $\mathit W_{tb}$ Vertex from the Measurement of Triple-Differential Angular Decay Rates of Single Top Quarks Produced in the t-Channel at $\sqrt {s }$ = 8 TeV with the ATLAS Detector
KHACHATRYAN 2016BU
PL B762 512 Measurement of the ${{\mathit W}}$ Boson Helicity Fractions in the Decays of Top Quark Pairs to Lepton + Jets Final States Produced in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 8 TeV
CHATRCHYAN 2013BH
JHEP 1310 167 Measurement of the ${{\mathit W}}$-Boson Helicity in Top-Quark Decays from ${\mathit {\mathit t}}{\mathit {\overline{\mathit t}}}$ Production in Lepton+Jets Events in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 7 TeV
AAD 2012BG
JHEP 1206 088 Measurement of the ${{\mathit W}}$ Boson Polarization in Top Quark Decays with the ATLAS Detector