$W^{\pm} Z$ production at the LHC: fiducial cross sections and distributions in NNLO QCD

We report on the first fully differential calculation for $W^{\pm} Z$ production in hadron collisions up to next-to-next-to-leading order (NNLO) in QCD perturbation theory. Leptonic decays of the W and Z bosons are consistently taken into account, i.e. we include all resonant and non-resonant diagrams that contribute to the process $pp \to \ell^{\prime\pm}ν_{\ell}\prime\ell^+\ell^- + X$ both in the same-flavour ($\ell^{\prime} = \ell$) and the different-flavour ($\ell^{\prime} \neq \ell$) channel. Fiducial cross sections and distributions are presented in the presence of standard selection cuts applied in the experimental $W^{\pm} Z$ analyses by ATLAS and CMS at centre-of-mass energies of 8 and 13 TeV. As previously shown for the inclusive cross section, NNLO corrections increase the NNLO result by about 10%, thereby leading to an improved agreement with experimental data. The importance of NNLO accurate predictions is also shown in the case of new-physics scenarios, where, especially in high-$p_T$ categories, their impact can reach $\mathcal{O}(20%)$. The availability of differential NNLO predictions will play a crucial role in the rich physics programme that is based on precision studies of $W^{\pm} Z$ signatures at the LHC