CMS collaboration (2135 authors)Hollar, JonathanNayak, ArunaBargassa, PedrameBeirão Da Cruz E Silva, CristóvãoFaccioli, PietroFerreira Parracho, Pedro GuilhermeGallinaro, MicheleLloret Iglesias, LaraNguyen, FedericoRodrigues Antunes, JoaoSeixas, JoaoVarela, JoaoVischia, PietroDavid Tinoco Mendes, AndreSilva, PedroMusella, PasqualePela, JoaoLeonardo, Nuno2019-02-042019-02-042015-09-25http://dx.doi.org/10.1016/j.physletb.2015.09.057http://hdl.handle.net/10400.26/26808The first study of W boson production in pPb collisions is presented, for bosons decaying to a muon or electron, and a neutrino. The measurements are based on a data sample corresponding to an integrated luminosity of 34.6 nb$^{-1}$ at a nucleon-nucleon centre-of-mass energy of $\sqrt{s_{\mathrm{NN}}}$ =5.02 TeV, collected by the CMS experiment. The W boson differential cross sections, lepton charge asymmetry, and forward–backward asymmetries are measured for leptons of transverse momentum exceeding 25 GeV/ c , and as a function of the lepton pseudorapidity in the |ηlab|<2.4 range. Deviations from the expectations based on currently available parton distribution functions are observed, showing the need for including W boson data in nuclear parton distribution global fits.engjournal article2019-02-04