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

${\mathit {\mathit t}}$-quark FCNC Couplings $\kappa {}^{utg}/\Lambda $ and $\kappa {}^{ctg}/\Lambda $

INSPIRE   PDGID:
Q007TUG
VALUE (TeV${}^{-1}$) CL% DOCUMENT ID TECN  COMMENT
• • We do not use the following data for averages, fits, limits, etc. • •
1
AAD
2022T
 ATLS ${{\mathit u}}$ ${{\mathit g}}$ $\rightarrow$ ${{\mathit t}}$ , ${{\mathit c}}$ ${{\mathit g}}$ $\rightarrow$ ${{\mathit t}}$
$<0.0041$ 95 2
KHACHATRYAN
2017G
 CMS $\vert {{\mathit \kappa}}{}^{tug}\vert /\Lambda $
$<0.018$ 95 2
KHACHATRYAN
2017G
 CMS $\vert {{\mathit \kappa}}{}^{tcg}\vert /\Lambda $
$<0.010$ 95 3
AAD
2016AS
 ATLS ${{\mathit \kappa}}{}^{tug}/\Lambda $
$<0.023$ 95 3
AAD
2016AS
 ATLS ${{\mathit \kappa}}{}^{tcg}/\Lambda $
$<0.0069$ 95 4
AAD
2012BP
 ATLS ${{\mathit t}^{tug}}/{{\mathit \Lambda}}$ (${{\mathit t}^{tcg}}$ = 0)
$<0.016$ 95 4
AAD
2012BP
 ATLS ${{\mathit t}^{tcg}}/{{\mathit \Lambda}}$ (${{\mathit t}^{tug}}$ = 0)
$<0.013$ 95 5
ABAZOV
2010K
 D0 ${{\mathit \kappa}}{}^{tug}/\Lambda $
$<0.057$ 95 5
ABAZOV
2010K
 D0 ${{\mathit \kappa}}{}^{tcg}/\Lambda $
$<0.018$ 95 6
AALTONEN
2009N
 CDF ${{\mathit \kappa}}{}^{tug}/\Lambda $ (${{\mathit \kappa}}{}^{tcg}$ = 0)
$<0.069$ 95 6
AALTONEN
2009N
 CDF ${{\mathit \kappa}}{}^{tcg}/\Lambda $ (${{\mathit \kappa}}{}^{tug}$ = 0)
$<0.037$ 95 7
ABAZOV
2007V
 D0 $\kappa {}^{utg}/\Lambda $
$<0.15$ 95 7
ABAZOV
2007V
 D0 $\kappa {}^{ctg}/\Lambda $
1  AAD 2022T based on 139 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 13 TeV. The results are obtained from the 95$\%$ CL upper limits on the single top-quark productions ${\mathit \sigma (}$ ${{\mathit u}}$ ${{\mathit g}}$ $\rightarrow$ ${{\mathit t}}{)}\cdot{}$B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit b}}{{\mathit W}}$ )$\cdot{}$B( ${{\mathit W}}$ $\rightarrow$ ${{\mathit \ell}}{{\mathit \nu}}$ ) $<$ 3.0 pb and ${\mathit \sigma (}$ ${{\mathit c}}$ ${{\mathit g}}$ $\rightarrow$ ${{\mathit t}}{)}\cdot{}$B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit b}}{{\mathit W}}$ )$\cdot{}$B( ${{\mathit W}}$ $\rightarrow$ ${{\mathit \ell}}{{\mathit \nu}}$ ) $<$ 4.7 pb. These are interpreted as limits on couplings in an EFT $\vert C{}^{ut}_{uG}\vert /\Lambda {}^{2}$ $<$ 0.057 TeV${}^{-2}$ and $\vert C{}^{ct}_{uG}\vert /\Lambda {}^{2}$ $<$ 0.14 TeV${}^{-2}$. The results also correspond to B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit u}}{{\mathit g}}$ ) $<$ $6.1 \times 10^{-5}$ and B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit c}}{{\mathit g}}$ ) $<$ $3.7 \times 10^{-4}$.
2  KHACHATRYAN 2017G based on 5.0 and 19.7 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 7 and 8 TeV, respectively. ${{\mathit t}}$ -channel single top production is used. The result corresponds to B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit u}}{{\mathit g}}$ ) $<$ $2.0 \times 10^{-5}$ or B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit c}}{{\mathit g}}$ ) $<$ $4.1 \times 10^{-4}$.
3  AAD 2016AS based on 20.3 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 8 TeV. The results are obtained from the 95$\%$ CL upper limit on the single top-quark production ${\mathit \sigma (}$ ${{\mathit q}}$ ${{\mathit g}}$ $\rightarrow$ ${{\mathit t}}{)}\cdot{}$B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit b}}{{\mathit W}}$ )B( ${{\mathit W}}$ $\rightarrow$ ${{\mathit l}}{{\mathit \nu}}$ ) $<$ 2.9 pb, B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit u}}{{\mathit g}}$ ) $<$ $4.0 \times 10^{-5}$ and B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit c}}{{\mathit g}}$ ) $<$ $20 \times 10^{-5}$.
4  Based on 2.05 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 7 TeV. The results are obtained from the 95$\%$ CL upper limit on the single top-quark production ${\mathit \sigma (}$ ${{\mathit q}}$ ${{\mathit g}}$ $\rightarrow$ ${{\mathit t}}{)}\cdot{}$B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit b}}{{\mathit W}}$ ) $<$ 3.9 pb, for ${{\mathit q}}={{\mathit u}}$ or ${{\mathit q}}={{\mathit c}}$, B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit u}}{{\mathit g}}$ ) $<$ $5.7 \times 10^{-5}$ and B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit u}}{{\mathit g}}$ ) $<$ $2.7 \times 10^{-4}$.
5  Based on 2.3 fb${}^{-1}$ of data in ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at $\sqrt {s }$ = 1.96 TeV. Upper limit of single top quark production cross section 0.20 pb and 0.27 pb via FCNC $\mathit t-u-g$ and $\mathit t-c-g$ couplings, respectively, lead to the bounds without assuming the absence of the other coupling. B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit u}}{+}$ ${{\mathit g}}$ ) $<$ $2.0 \times 10^{-4}$ and B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit c}}{+}$ ${{\mathit g}}$ ) $<$ $3.9 \times 10^{-3}$ follow.
6  Based on 2.2 fb${}^{-1}$ of data in ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at $\sqrt {s }$ = 1.96 TeV. Upper limit of single top quark production cross section ${\mathit \sigma (}$ ${{\mathit u}{(c)}}$ ${+}$ ${{\mathit g}}$ $\rightarrow$ ${{\mathit t}}{)}$ $<$ 1.8 pb (95$\%$ CL) via FCNC $\mathit t-u-g$ and $\mathit t-c-g$ couplings lead to the bounds. B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit u}}{+}$ ${{\mathit g}}$ ) $<$ $3.9 \times 10^{-4}$ and B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit c}}{+}$ ${{\mathit g}}$ ) $<$ $5.7 \times 10^{-3}$ follow.
7  Result is based on 230 pb${}^{-1}$ of data at $\sqrt {s }$ = 1.96 TeV. Absence of single top quark production events via FCNC $\mathit t-u-g$ and $\mathit t-c-g$ couplings lead to the upper bounds on the dimensioned couplings, $\kappa {}^{utg}/\Lambda $ and $\kappa {}^{ctg}/\Lambda $, respectively.
References:
AAD 2022T
EPJ C82 334 Search for flavour-changing neutral-current interactions of a top quark and a gluon in pp collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
KHACHATRYAN 2017G
JHEP 1702 028 Search for Anomalous ${{\mathit W}}{\mathit {\mathit t}}{\mathit {\mathit b}}$ Couplings and Flavour-Changing Neutral Currents in ${{\mathit t}}$-Channel Single Top Quark Production in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 7 and 8 TeV
AAD 2016AS
EPJ C76 55 Search for Single Top-Quark Production via Flavour-Changing Neutral Currents at 8 TeV with the ATLAS Detector
Also
EPJ C82 70 (errat.) Search for single top-quark production via flavour-changing neutral currents at 8 TeV with the ATLAS detector
AAD 2012BP
PL B712 351 Search for FCNC (flavour-changing neutral-currents) Single Top-Quark Production at $\sqrt {s }$ = 7 TeV with the ATLAS Detector
ABAZOV 2010K
PL B693 81 Search for Flavor Changing Neutral Currents via Quark-Gluon Couplings in Single Top Quark Production using 2.3 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\overline{\mathit p}}}$ Collisions
AALTONEN 2009N
PRL 102 151801 Search for Top-Quark Production via Flavor-Changing Neutral Currents in ${{\mathit W}}$+1 Jet Events at CDF
ABAZOV 2007V
PRL 99 191802 Search for Production of Single Top Quarks Via tcg and tug Flavor-Changing-Neutral-Current Couplings