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 Te . The data correspond to an integrated luminosity of 35.7 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∗(2010)± mesons that decay via D∗(2010)± → D0 + π± → K∓ + π± + π± . A cross section is measured in the fiducial region defined by the muon transverse momentum pTμ > 26 Ge , muon pseudorapidity |ημ| < 2.4 , and charm quark transverse momentum pTc > 5 Ge . The inclusive cross section for this kinematic range is [Formula: see text] . 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.