Precise predictions for the angular coefficients in Z-boson production

The angular distributions of lepton pairs in the Drell–Yan process can provide a wealth of information on the underlying QCD production mechanisms. It is possible to parameterise these dynamics in terms of a set of frame dependent angular coefficients, $A_{i=0,...,7}$, which depend on the invariant mass, transverse momentum, and rapidity of the final-state lepton pair. Motivated by recent measurements of these coefficients by both ATLAS and CMS, we perform a precision study of the angular coefficients at $\mathcal{O}(α^{3}_{s})$ in perturbative QCD. We make predictions relevant for pp collisions at $\sqrt{s} =$ 8 TeV, and perform comparisons with the available ATLAS and CMS data. The compatibility of this data is assessed by performing a partial $χ^2$ test with respect to the central theoretical prediction which shows that $χ^2/N_{\scriptstyle/text{data}}$ is significantly reduced by going from $O(α^{2}_{s})$ to $O(α^{3}_{s})$.