${\mathit {\mathit t}}$-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.

$\vert $f$_{LV}V_{tb}\vert $

INSPIRE   JSON  (beta) PDGID:
Q007A02
Assumed that the top-quark-related CKM matrix elements obey the relation $\vert V_{td}\vert $, $\vert V_{ts}\vert {}\ll\vert V_{tb}\vert $ and a form factor f$_{LV}$ is determined for each production mode and centre-of-mass energy.
VALUE DOCUMENT ID TECN  COMMENT
$\bf{ 0.999 \pm0.017}$ OUR AVERAGE
$1.015$ $\pm0.031$ 1
AAD
2024AL
 ATLS 13 TeV, ${{\mathit t}}$-channel single top
$0.97$ $\pm0.10$ 2
AAD
2024BS
 ATLS 13 TeV, ${{\mathit W}}{{\mathit t}}$ production
$0.94$ ${}^{+0.11}_{-0.10}$ 3
AAD
2024M
 ATLS 5.02 TeV, ${{\mathit t}}$-channel single top
$0.988$ $\pm0.024$ 4
SIRUNYAN
2020AZ
 CMS 13 TeV, ${{\mathit t}}$-channel single top
$1.02$ $\pm0.04$ $\pm0.02$ 5
AABOUD
2019R
 LHC ATLAS + CMS at 7, 8 TeV
1  AAD 2024AL based on 140 fb${}^{-1}$ of data at $\sqrt {s }$ = 13 TeV. The value is extracted by dividing the measured value ${\mathit \sigma (}{{\mathit t}}{{\mathit q}}{+}$ ${{\overline{\mathit t}}}{{\mathit q}}{)}$ = $221$ $\pm13$ pb by the SM expectation of $214$ $\pm3.4$(scale+PDF)$\pm1.8({{\mathit \Delta}}$m$_{top}$) pb in the ${{\mathit t}}$-channel single-top production mode. Restricting 0 $<$ $\vert \mathit V_{\mathit tb}\vert $ $<$ 1 and setting f$_{LV}$ = 1, a lower limit $\vert \mathit V_{\mathit tb}\vert $ $>$ 0.95 (95$\%$ CL) is obtained within the SM.
2  AAD 2024BS based on 140 fb${}^{-1}$ of data at $\sqrt {s }$ = 13 TeV. The value is extracted by comparing the measured cross section for a single top quark in association with a ${{\mathit W}}$ boson with the SM prediction.
3  AAD 2024M based on 255 pb${}^{-1}$ of data at $\sqrt {s }$ = 5.02 TeV. The value is extracted from the cross section of the ${{\mathit t}}$-channel single-top production ${\mathit \sigma (}{{\mathit t}}{{\mathit q}}{+}$ ${{\overline{\mathit t}}}{{\mathit q}}{)}$ = $27.1$ ${}^{+4.4}_{-4.1}{}^{+4.4}_{-3.7}$ pb.
4  SIRUNYAN 2020AZ based on 35.9 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 13 TeV. Final states enriched in single top quark ${{\mathit t}}$-channel events are used. Several theories beyond the standard model are considered, and by releasing all constraints among the involved parameters. Under the standard model assumption of CKM unitarity, the values are found to be $\vert V_{tb}\vert $ $>$ 0.970 and $\vert V_{td}\vert ^2$ + $\vert V_{ts}\vert ^2$ $<$ 0.057, both at 95$\%$ CL.
5  The combination of single-top production cross-section measurements in the ${{\mathit t}}$-channel, ${{\mathit t}}{{\mathit W}}$, and ${{\mathit s}}$-channel production modes from ATLAS and CMS at $\sqrt {s }$ = 7 and 8 TeV.
References