Measurements of the pp $\to$ WZ inclusive and differential production cross section and constraints on charged anomalous triple gauge couplings at $\sqrt{s} =$ 13 TeV

The WZ production cross section is measured in proton-proton collisions at a centre-of-mass energy $ \sqrt{s} $ = 13 TeV using data collected with the CMS detector, corresponding to an integrated luminosity of 35.9 fb$^{−1}$. The inclusive cross section is measured to be σ$_{tot}$(pp → WZ) = 48.09$_{− 0.96}^{+ 1.00}$ (stat)$_{− 0.37}^{+ 0.44}$ (theo)$_{− 2.17}^{+ 2.39}$ (syst) ± 1.39(lum) pb, resulting in a total uncertainty of −2.78/+2.98 pb. Fiducial cross section and ratios of charge-dependent cross section measurements are provided. Differential cross section measurements are also presented with respect to three variables: the Z boson transverse momentum p$_{T}$, the leading jet p$_{T}$, and the M(WZ) variable, defined as the invariant mass of the system composed of the three leptons and the missing transverse momentum. Differential measurements with respect to the W boson p$_{T}$, separated by charge, are also shown. Results are consistent with standard model predictions, favouring next-to-next-to-leading-order predictions over those at next-to-leading order. Constraints on anomalous triple gauge couplings are derived via a binned maximum likelihood fit to the M(WZ) variable.