${\mathit {\mathit t}}$-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:
Q007TVP
VALUE CL% DOCUMENT ID TECN  COMMENT
$\bf{ -0.005 \pm0.007}$ OUR AVERAGE
$-0.008$ $\pm0.005$ $\pm0.006$ 1
AAD
2020Y
 LHC ATLAS+CMS combined
$-0.045$ $\pm0.044$ $\pm0.058$ 2
AALTONEN
2013D
 CDF ${{\mathit F}_{{{+}}}}$ = B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit W}_{{{+}}}}{{\mathit b}}$)
$0.008$ $\pm0.012$ $\pm0.014$ 3
CHATRCHYAN
2013BH
 CMS ${{\mathit F}_{{{+}}}}$ = B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit W}_{{{+}}}}{{\mathit b}}$)
$0.01$ $\pm0.05$ 4
AAD
2012BG
 ATLS ${{\mathit F}_{{{+}}}}$ = B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit W}_{{{+}}}}{{\mathit b}}$)
$0.023$ $\pm0.041$ $\pm0.034$ 5
ABAZOV
2011C
 D0 ${{\mathit F}_{{{+}}}}$ = B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit W}_{{{+}}}}{{\mathit b}}$)
$0.11$ $\pm0.15$ 6
AFFOLDER
2000B
 CDF ${{\mathit F}_{{{+}}}}$ = B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit W}}_{+}$ ${{\mathit b}}$)
• • We do not use the following data for averages, fits, limits, etc. • •
$< 0.036 \pm0.006$ 95 7
AABOUD
2017BB
 ATLS ${{\mathit F}_{{{+}}}}$ = ${{\mathit f}_{{{1}}}}{{\mathit f}_{{{1}}}^{+}}$, Repl. by AAD 2020Y
$-0.004$ $\pm0.005$ $\pm0.014$ 8
KHACHATRYAN
2016BU
 CMS ${{\mathit F}_{{{+}}}}$ = B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit W}_{{{+}}}}{{\mathit b}}$), Repl. by AAD 2020Y
$-0.033$ $\pm0.034$ $\pm0.031$ 9
AALTONEN
2012Z
 TEVA ${{\mathit F}_{{{+}}}}$ = B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit W}_{{{+}}}}{{\mathit b}}$)
$-0.01$ $\pm0.02$ $\pm0.05$ 10
AALTONEN
2010Q
 CDF Repl. by AALTONEN 2013D
$-0.04$ $\pm0.04$ $\pm0.03$ 11
AALTONEN
2009Q
 CDF Repl. by AALTONEN 2010Q
$0.119$ $\pm0.090$ $\pm0.053$ 12
ABAZOV
2008B
 D0 Repl. by ABAZOV 2011C
$0.056$ $\pm0.080$ $\pm0.057$ 13
ABAZOV
2007D
 D0 ${{\mathit F}_{{{+}}}}$ = B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit W}_{{{+}}}}{{\mathit b}}$)
$0.05$ ${}^{+0.11}_{-0.05}$ $\pm0.03$ 14
ABULENCIA
2007I
 CDF ${{\mathit F}_{{{+}}}}$ = B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit W}_{{{+}}}}{{\mathit b}}$)
$<0.26$ 95 14
ABULENCIA
2007I
 CDF ${{\mathit F}_{{{+}}}}$ = B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit W}_{{{+}}}}{{\mathit b}}$)
$<0.27$ 95 15
ABULENCIA
2006U
 CDF ${{\mathit F}_{{{+}}}}$ = B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit W}_{{{+}}}}{{\mathit b}}$)
$0.00$ $\pm0.13$ $\pm0.07$ 16
ABAZOV
2005L
 D0 ${{\mathit F}_{{{+}}}}$ = B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit W}_{{{+}}}}{{\mathit b}}$)
$<0.25$ 95 16
ABAZOV
2005L
 D0 ${{\mathit F}_{{{+}}}}$ = B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit W}_{{{+}}}}{{\mathit b}}$)
$<0.24$ 95 17
ACOSTA
2005D
 CDF ${{\mathit F}_{{{+}}}}$ = B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit W}_{{{+}}}}{{\mathit b}}$)
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 estimated from the measurements of $\mathit F_{0}$ and $\mathit F_{-}$ assuming unitarity. The value is consistent with the NNLO SM prediction of $0.0017$ $\pm0.0001$ for ${\mathit m}_{{{\mathit t}}}$ = $172.8$ $\pm1.3$ GeV.
2  Based on 8.7 fb${}^{-1}$ of data in ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at $\sqrt {s }$ = 1.96 TeV using ${{\mathit t}}{{\overline{\mathit t}}}$ events with ${{\mathit \ell}}$ + $\not E_T$ + ${}\geq{}$4 jets(${}\geq{}$1 ${{\mathit b}}$), and under the constraint F$_{0}$ + F$_{+}$ + F$_{-}$ = 1. The statstical errors of F$_{0}$ and F$_{+}$ are correlated with correlation coefficient $\rho (F_{0},F_{+}$) = $-0.69$.
3  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{}$4 jets using a constrained kinematic fit.
4  Based on 1.04 fb${}^{-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{}$2j.
5  Results are based on 5.4 fb${}^{-1}$ of data in ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at 1.96 TeV, including those of ABAZOV 2008B. Under the SM constraint of ${{\mathit f}_{{{0}}}}$ = 0.698 (for ${\mathit m}_{{{\mathit t}}}$ = 173.3 GeV, ${\mathit m}_{{{\mathit W}}}$ = 80.399 GeV), ${{\mathit f}_{{{+}}}}$ = $0.010$ $\pm0.022$ $\pm0.030$ is obtained.
6  AFFOLDER 2000B studied the angular distribution of leptonic decays of ${{\mathit W}}$ bosons in ${{\mathit t}}$ $\rightarrow$ ${{\mathit W}}{{\mathit b}}$ events. The ratio $\mathit F_{0}$ is the fraction of the helicity zero (longitudinal) ${{\mathit W}}~$bosons in the decaying top quark rest frame. B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit W}}_{+}$ ${{\mathit b}}$) is the fraction of positive helicity (right-handed) positive charge ${{\mathit W}}~$bosons in the top quark decays. It is obtained by assuming the Standard Model value of $\mathit F_{0}$.
7  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 ${{\mathit F}_{{{+}}}}$ = ${{\mathit f}_{{{1}}}}{{\mathit f}_{{{1}}}^{+}}$. See this paper for constraints on other couplings not included here.
8  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 result is consistent with the NNLO SM prediction of $0.0017$ $\pm0.0001$ for ${\mathit m}_{{{\mathit t}}}$ = $172.8$ $\pm1.3$ GeV.
9  Based on 2.7 and 5.1 fb${}^{-1}$ of CDF data in ${{\mathit \ell}}$ + jets and dilepton channels, and 5.4 fb${}^{-1}$ of D0 data in ${{\mathit \ell}}$ + jets and dilepton channels. ${{\mathit F}_{{{0}}}}$ = $0.682$ $\pm0.035$ $\pm0.046$ if ${{\mathit F}_{{{+}}}}$ = 0.0017(1), while ${{\mathit F}_{{{+}}}}$ = $-0.015$ $\pm0.018$ $\pm0.030$ if ${{\mathit F}_{{{0}}}}$ = 0.688(4), where the assumed fixed values are the SM prediction for ${\mathit m}_{{{\mathit t}}}$ = $173.3$ $\pm1.1$ GeV and ${\mathit m}_{{{\mathit W}}}$ = $80.399$ $\pm0.023$ GeV.
10  Results are based on 2.7 fb${}^{-1}$ of data in ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at $\sqrt {s }$ = 1.96 TeV. ${{\mathit F}_{{{0}}}}$ result is obtained by assuming ${{\mathit F}_{{{+}}}}$ = 0, while ${{\mathit F}_{{{+}}}}$ result is obtained for ${{\mathit F}_{{{0}}}}$ = 0.70, the SM value. Model independent fits for the two fractions give ${{\mathit F}_{{{0}}}}$ = $0.88$ $\pm0.11$ $\pm0.06$ and ${{\mathit F}_{{{+}}}}$ = $-0.15$ $\pm0.07$ $\pm0.06$ with correlation coefficient of $-0.59$. The results are for ${\mathit m}_{{{\mathit t}}}$ = 175 GeV.
11  Results are based on 1.9 fb${}^{-1}$ of data in ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at $\sqrt {s }$ = 1.96 TeV. ${{\mathit F}_{{{0}}}}$ result is obtained assuming ${{\mathit F}_{{{+}}}}$ = 0, while ${{\mathit F}_{{{+}}}}$ result is obtained for ${{\mathit F}_{{{0}}}}$ = 0.70, the SM values. Model independent fits for the two fractions give ${{\mathit F}_{{{0}}}}$ = $0.66$ $\pm0.16$ $\pm0.05$ and ${{\mathit F}_{{{+}}}}$ = $-0.03$ $\pm0.06$ $\pm0.03$.
12  Based on 1 fb${}^{-1}$ at $\sqrt {s }$ = 1.96 TeV.
13  Based on 370 pb${}^{-1}$ of data at $\sqrt {s }$ = 1.96 TeV, using the ${{\mathit \ell}}$ + jets and dilepton decay channels. The result assumes ${{\mathit F}_{{{0}}}}$ = 0.70, and it gives ${{\mathit F}_{{{+}}}}$ $<$ 0.23 at 95$\%$ CL.
14  Based on 318 pb${}^{-1}$ of data at $\sqrt {s }$ = 1.96 TeV.
15  Based on 200 pb${}^{-1}$ of data at $\sqrt {s }$ = 1.96 TeV. ${{\mathit t}}$ $\rightarrow$ ${{\mathit W}}{{\mathit b}}$ $\rightarrow$ ${{\mathit \ell}}{{\mathit \nu}}{{\mathit b}}$ (${{\mathit \ell}}$ = ${{\mathit e}}$ or ${{\mathit \mu}}$). The errors are stat + syst.
16  ABAZOV 2005L studied the angular distribution of leptonic decays of ${{\mathit W}}$ bosons in ${{\mathit t}}{{\overline{\mathit t}}}$ events, where one of the ${{\mathit W}}$'s from ${{\mathit t}}$ or ${{\overline{\mathit t}}}$ decays into ${{\mathit e}}$ or ${{\mathit \mu}}$ and the other decays hadronically. The fraction of the ``+'' helicity ${{\mathit W}}$ boson is obtained by assuming ${{\mathit F}_{{{0}}}}$ = 0.7, which is the generic prediction for any linear combination of V and A currents. Based on $230$ $\pm15$ pb${}^{-1}$ of data at $\sqrt {s }$ = 1.96 TeV.
17  ACOSTA 2005D measures the ${{\mathit m}^{2}}_{{{\mathit \ell}} {+} {{\mathit b}}}$ distribution in ${{\mathit t}}{{\overline{\mathit t}}}$ production events where one or both ${{\mathit W}}$'s decay leptonically to ${{\mathit \ell}}$ = ${{\mathit e}}$ or ${{\mathit \mu}}$, and finds a bound on the V+A coupling of the ${{\mathit t}}{{\mathit b}}{{\mathit W}}$ vertex. By assuming the SM value of the longitudinal ${{\mathit W}}$ fraction ${{\mathit F}_{{{0}}}}$ = B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit W}_{{{0}}}}{{\mathit b}}$) = 0.70, the bound on ${{\mathit F}}_{+}$ is obtained. If the results are combined with those of AFFOLDER 2000B, the bounds become ${{\mathit F}}_{V+A}$ $<$ 0.61 (95$\%$ CL) and ${{\mathit F}_{{{+}}}}$ $<$ 0.18 (95 $\%$CL), respectively. Based on $109$ $\pm7$ pb${}^{-1}$ of data at $\sqrt {s }$ = 1.8 TeV (run I).
References