Speaker
Description
We provide state-of-the art SCETlib predictions for the $W$ and $Z/\gamma^∗$ transverse-momentum ($q_T$) distributions at the LHC at complete three-loop order in resummed perturbation theory (N$^3$LL$'$) and matched to available fixed order. We compare our predictions to high-precision measurements by the ATLAS and CMS experiments. We pay particular attention to the estimation of perturbative theory uncertainties via profile scale variation and the parametric uncertainty from the collinear PDF set and the value of the strong coupling, in turn allowing us to assess to what extent they may compensate the impact of the nonperturbative TMD structure of the proton and its evolution at small $q_T$. We find intriguing evidence that the normalized ATLAS and CMS $Z$ $q_T$ spectra may prefer a lower strong coupling than the PDG value, with important implications for the extraction of TMD PDFs from LHC data.
