Measurements of the associated production of a W boson and a charm quark in proton–proton collisions at $\sqrt{s}=8\phantom{\rule{0.166667em}{0ex}}\text{TeV}$

Measurements of the associated production of a W boson and a charm ( $\text{c}$ ) quark in proton–proton collisions at a centre-of-mass energy of 8 $\phantom{\rule{0.166667em}{0ex}}\text{TeV}$ are reported. The analysis uses a data sample corresponding to a total integrated luminosity of 19.7 $\phantom{\rule{0.166667em}{0ex}}{\text{fb}}^{-1}$ collected by the CMS detector at the LHC. The W bosons are identified through their leptonic decays to an electron or a muon, and a neutrino. Charm quark jets are selected using distinctive signatures of charm hadron decays. The product of the cross section and branching fraction $\sigma \left(\text{pp}\to \text{W}+\text{c}+\text{X}\right)B\left(\text{W}\to \ell \nu \right)$ , where $\ell =\text{e}$ or $\mu $ , and the cross section ratio $\sigma \left(\text{pp}\to {\text{W}}^{+}+\overline{\text{c}}+\text{X}\right)/\sigma \left(\text{pp}\to {\text{W}}^{-}+\text{c}+\text{X}\right)$ are measured in a fiducial volume and differentially as functions of the pseudorapidity and of the transverse momentum of the lepton from the W boson decay. The results are compared with theoretical predictions. The impact of these measurements on the determination of the strange quark distribution is assessed.