What are the Standard Model predictions for both the vector and axial-vector couplings of the $Z$ boson to $b$ quarks ($g_V^b$ and $g_A^b$)?
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This is but a blunt plugin in the expression of your PDG, (10.2), (10.5), no? $$ g_V=-1/2 + 2/3 \sin^2\theta_W, \qquad g_A=-1/2 . $$
answered Jan 6, 2021 at 17:04
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$\begingroup$ And is there any SM prediction for $\sin{\theta_W}$? $\endgroup$– jmaguireCommented Jan 6, 2021 at 17:11
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1$\begingroup$ Mea culpa, squared, fixed. The SM does not predict $\theta_W$, so it is determined by experiment. Table 10.2 in the PDG gives you several values, all around 0.23 for the square of the sine. $\endgroup$ Commented Jan 6, 2021 at 17:21