${\boldsymbol {\boldsymbol t}}$-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.

${\boldsymbol \sigma (}$ ${{\boldsymbol H}}{{\boldsymbol t}}{{\overline{\boldsymbol t}}}{)}$ /${\boldsymbol \sigma (}$ ${{\boldsymbol H}}{{\boldsymbol t}}{{\overline{\boldsymbol t}}}{)}_{SM}$ INSPIRE search

VALUE CL% DOCUMENT ID TECN  COMMENT
• • • We do not use the following data for averages, fits, limits, etc. • • •
$0.72$ $\pm0.24$ $\pm0.38$ 1
SIRUNYAN
2019R
CMS ${{\mathit H}}{{\mathit t}}{{\overline{\mathit t}}}$ ( ${{\mathit H}}$ $\rightarrow$ ${{\mathit b}}{{\overline{\mathit b}}}$ , ${{\mathit t}}{{\overline{\mathit t}}}$ $\rightarrow$ ${{\mathit \ell}}$ +jets or dilepton)
$0.9$ $\pm0.7$ $\pm1.3$ 2
SIRUNYAN
2018BD
CMS ${{\mathit H}}{{\mathit t}}{{\overline{\mathit t}}}$ ( ${{\mathit H}}$ $\rightarrow$ ${{\mathit b}}{{\overline{\mathit b}}}$ , ${{\mathit t}}{{\overline{\mathit t}}}$ $\rightarrow$ all jets)
$1.26$ ${}^{+0.31}_{-0.26}$ 3
SIRUNYAN
2018L
CMS combination of CMS
$<6.7$ 95 4
AAD
2015
ATLS ${{\mathit H}}{{\mathit t}}{{\overline{\mathit t}}}$ ; ${{\mathit H}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$
$2.8$ $\pm1.0$ 5
KHACHATRYAN
2014H
CMS ${{\mathit H}}$ $\rightarrow$ ${{\mathit b}}{{\overline{\mathit b}}}$ , ${{\mathit \tau}_{{h}}}{{\mathit \tau}_{{h}}}$ , ${{\mathit \gamma}}{{\mathit \gamma}}$ , ${{\mathit W}}{{\mathit W}}$ $/$ ${{\mathit Z}}{{\mathit Z}}$ (leptons)
1  SIRUNYAN 2019R based on 35.9 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at 13 TeV. Multivariate techniques are employed to separate the signal from the dominant ${{\mathit t}}{{\overline{\mathit t}}}$ +jets background. The result is for ${\mathit m}_{{{\mathit H}}}$ = 125 GeV. The measured ratio corresponds to a signal significance of 1.6$\sigma $ above the background-only hypothesis.
2  SIRUNYAN 2018BD based on 35.9 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at 13 TeV. A combined fit of signal and background templates to data is performed in six event categories separated by jet and ${{\mathit b}}$-jet multiplicities. An upper limit of 3.8 is obtained for the cross section ratio.
3  SIRUNYAN 2018L based on up to 5.1, 19.7, and 35.9 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at 7, 8, and 13 TeV, respectively. An excess of events is observed, with a significance of 5.2 standard deviations, over the expectation from the background-only hypothesis. The result is for the Higgs boson mass of 125.09 GeV.
4  Based on 4.5 fb${}^{-1}$ of data at 7 TeV and 20.3 fb${}^{-1}$ at 8 TeV. The result is for ${\mathit m}_{{{\mathit H}}}$ = 125.4 GeV. The measurement constrains the top quark Yukawa coupling strength parameter $\kappa _{t}$ = ${{\mathit Y}_{{t}}}/{{\mathit Y}_{{t}}^{SM}}$ to be $-1.3$ $<$ $\kappa _{t}$ $<$ 8.0 (95$\%$ CL).
5  Based on 5.1 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at 7 TeV and 19.7 fb${}^{-1}$ at 8 TeV. The results are obtained by assuming the SM decay branching fractions for the Higgs boson of mass 125.6 GeV. The signal strength for individual Higgs decay channels are given in Fig. 13, and the preferred region in the ($\kappa _{V}$, $\kappa _{f}$) space is given in Fig. 14.
  References:
SIRUNYAN 2019R
JHEP 1903 026 Search for $ \mathrm{t}\overline{\mathrm{t}}\mathrm{H} $ production in the $ \mathrm{H}\to \mathrm{b}\overline{\mathrm{b}} $ decay channel with leptonic $ \mathrm{t}\overline{\mathrm{t}} $ decays in proton-proton collisions at $ \sqrt{s}=13 $ TeV
SIRUNYAN 2018BD
JHEP 1806 101 Search for $\mathrm{t}\overline{\mathrm{t}}$H production in the all-jet final state in proton-proton collisions at $\sqrt{s}=$ 13 TeV
SIRUNYAN 2018L
PRL 120 231801 Observation of $\mathrm{t\overline{t}}$H production
AAD 2015
PL B740 222 Search for ${{\mathit H}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}$ Produced in Association with Top Quarks and Constraints on the Yukawa Coupling between the Top Quark and the Higgs Boson using Data Taken at 7 TeV and 8 TeV with the ATLAS Detector
KHACHATRYAN 2014H
JHEP 1409 087 Search for the Associated Production of the Higgs Boson with a Top-quark Pair