Measurement of associated production of a W boson and a charm quark in proton-proton collisions at s = 13 Te

Abstract

Measurements are presented of associated production of a $W$ boson and a charm quark ( $W+c$ ) in proton-proton collisions at a center-of-mass energy of 13 $\text{Te}$ . The data correspond to an integrated luminosity of 35.7 ${\text{fb}}^{-1}$ collected by the CMS experiment at the CERN LHC. The $W$ bosons are identified by their decay into a muon and a neutrino. The charm quarks are tagged via the full reconstruction of $D^{\ast }{\left(2010\right)}^{\pm }$ mesons that decay via $D^{\ast }{\left(2010\right)}^{\pm }\to D^0+{\pi }^{\pm }\to K^{\mp }+{\pi }^{\pm }+{\pi }^{\pm }$ . A cross section is measured in the fiducial region defined by the muon transverse momentum $p_T^{\mu }>26\text{Ge}$ , muon pseudorapidity $|{\eta }^{\mu }|<2.4$ , and charm quark transverse momentum $p_T^c>5\text{Ge}$ . The inclusive cross section for this kinematic range is $\sigma (W+c)=1026\pm 31\text{(stat)}\begin{array}{c}+76\\ -72\end{array}\text{(syst) pb}$ . The cross section is also measured differentially as a function of the pseudorapidity of the muon from the $W$ boson decay. These measurements are compared with theoretical predictions and are used to probe the strange quark content of the proton.