$\bf{
0.50 {}^{+0.04}_{0.05}}$

OUR AVERAGE

$0.532$ ${}^{+0.107}_{0.063}$ 

^{ 1} 


$0.501$ $\pm0.110$ 
156k 
^{ 2} 

D0 
$0.47$ ${}^{+0.05}_{0.33}$ 

^{ 3} 


$0.441$ ${}^{+0.207}_{0.173}$ $\pm0.067$ 
5026 
^{ 4} 

CDF 
• • • We do not use the following data for averages, fits, limits, etc. • • • 
$0.50$ ${}^{+0.12}_{0.05}$ 

^{ 5} 

ZEUS 
$0.57$ $\pm0.08$ 
1500 
^{ 6} 

H1 
^{1}
ABT 2016 determine the ${{\mathit Z}^{0}}$ couplings to ${{\mathit u}}$ and ${{\mathit d}}$quarks using the same techniques and data as ABRAMOWICZ 2016A but additionally use the published H1 polarised data.

^{2}
ABAZOV 2011D study ${{\mathit p}}$ ${{\overline{\mathit p}}}$ $\rightarrow$ ${{\mathit Z}}$ /${{\mathit \gamma}^{*}}{{\mathit e}^{+}}{{\mathit e}^{}}$ events using 5 fb${}^{1}$ data at $\sqrt {s }$ = 1.96 TeV. The candidate events are selected by requiring two isolated electromagnetic showers with $\mathit E_{T}>$ 25 GeV, at least one electron in the central region and the dielectron mass in the range $50  1000$ GeV. From the forwardbackward asymmetry, determined as a function of the dielectron mass, they derive the axial and vector couplings of the ${{\mathit u}}$ and ${{\mathit d}}$ quarks and the value of sin$^2\theta {}^{{{\mathit \ell}}}_{eff}$ = $0.2309$ $\pm0.0008$(stat)$\pm0.0006$(syst).

^{3}
LEPSLC 2006 is a combination of the results from LEP and SLC experiments using light quark tagging. s and dquark couplings are assumed to be identical.

^{4}
ACOSTA 2005M determine the forwardbackward asymmetry of ${{\mathit e}^{+}}{{\mathit e}^{}}$ pairs produced via ${{\mathit q}}$ ${{\overline{\mathit q}}}$ $\rightarrow$ ${{\mathit Z}}$ $/$ ${{\mathit \gamma}^{*}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{}}$ in 15 M( ${{\mathit e}^{+}}{{\mathit e}^{}}$ ) effective mass bins ranging from 40 GeV to 600 GeV. These results are used to obtain the vector and axialvector couplings of the ${{\mathit Z}}$ to the light quarks, assuming the electron couplings are as predicted by the Standard Model. Higher order radiative corrections have not been taken into account.

^{5}
ABRAMOWICZ 2016A determine the ${{\mathit Z}^{0}}$ couplings to ${{\mathit u}}$ and ${{\mathit d}}$quarks using the ZEUS polarised data from Run II together with the unpolarised data from both ZEUS and H1 Collaborations for Run I and unpolarised H1 data from Run II.

^{6}
AKTAS 2006 fit the neutral current (1.5${}\leq{}Q{}^{2}{}\leq{}$30,000 GeV${}^{2}$) and charged current (1.5${}\leq{}Q{}^{2}{}\leq{}$15,000 GeV${}^{2}$) differential cross sections. In the determination of the ${{\mathit u}}$quark couplings the electron and ${{\mathit d}}$quark couplings are fixed to their standard model values.
