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

#### ${{\mathit F}_{{{V+A}}}}$

VALUE CL% DOCUMENT ID TECN  COMMENT
$\bf{<0.29}$ 95 1
 2007 G
CDF ${{\mathit F}_{{{V+A}}}}$ = B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit W}}{{\mathit b}_{{R}}}$ )
• • We do not use the following data for averages, fits, limits, etc. • •
$-0.06$ $\pm0.22$ $\pm0.12$ 1
 2007 G
CDF ${{\mathit F}_{{{V+A}}}}$ = B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit W}}{{\mathit b}_{{R}}}$ )
$<0.80$ 95 2
 2005 D
CDF ${{\mathit F}_{{{V+A}}}}$ = B( ${{\mathit t}}$ $\rightarrow$ ${{\mathit W}}{{\mathit b}_{{R}}}$ )
 1 Based on 700 pb${}^{-1}$ of data at $\sqrt {s }$ = 1.96 TeV.
 2 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:
 ABULENCIA 2007G
PRL 98 072001 Search for $\mathit V+\mathit A$ Current in Top-Quark Decays in ${{\mathit p}}{{\overline{\mathit p}}}$ Collisions at $\sqrt {s }$ = 1.96 TeV
 ACOSTA 2005D
PR D71 031101 Measurement of the ${{\mathit W}}$ Boson Polarization in top Decay at CDF at $\sqrt {s }$ = 1.8 TeV