Measurement of Inclusive $W$ and $Z$ Boson Production Cross Sections in $pp$ Collisions at $\sqrt{s}=8\mathrm{TeV}$

A measurement of total and fiducial inclusive $W$ and $\mathrm{Z}$ boson production cross sections in $pp$ collisions at $\sqrt{s}=8\mathrm{TeV}$ is presented. Electron and muon final states are analyzed in a data sample collected with the CMS detector corresponding to an integrated luminosity of $18.2\pm 0.5{\mathrm{pb}}^{-1}$. The measured total inclusive cross sections times branching fractions are $\sigma (pp\to WX)\times \mathcal{B}(W\to \ell \nu )=12.21\pm 0.03(\text{stat})\pm 0.24(\text{syst})\pm 0.32(\mathrm{lum})\mathrm{nb}$ and $\sigma (pp\to \mathrm{Z}X)\times \mathcal{B}(\mathrm{Z}\to {\ell }^{+}{\ell }^{-})=1.15\pm 0.01(\text{stat})\pm 0.02(\text{syst})\pm 0.03(\mathrm{lum})\mathrm{nb}$ for the dilepton mass in the range of 60—120 GeV. The measured values agree with next-to-next-to-leading-order QCD cross section calculations. Ratios of cross sections are reported with a precision of 2%. This is the first measurement of inclusive $W$ and $\mathrm{Z}$ boson production in proton-proton collisions at $\sqrt{s}=8\mathrm{TeV}$.