Abstract:
The production of \({W}^{±}\) bosons is studied in proton-lead (pPb) collisions at a nucleon-nucleon centre-of-mass energy of \(\sqrt{{s}_{\mathrm{NN}}}=8.16\phantom{\rule{0.25em}{0ex}}\text{TeV}\). Measurements are performed in the \({W}^{±}\to {\mu }^{±}{\nu }_{\mu }\) channel using a data sample corresponding to an integrated luminosity of \(173.4±6.1\phantom{\rule{0.25em}{0ex}}{\text{nb}}^{-1}\), collected by the CMS Collaboration at the LHC. The number of positively and negatively charged W bosons is determined separately in the muon pseudorapidity region in the laboratory frame \(|{\eta }_{\mathrm{lab}}^{\mu }|<2.4\) and transverse momentum \({p}_{T}^{\mu }>25\phantom{\rule{0.25em}{0ex}}\text{GeV}/c\). The \({W}^{±}\) boson differential cross sections, muon charge asymmetry, and the ratios of \({W}^{±}\) boson yields for the proton-going over the Pb-going beam directions are reported as a function of the muon pseudorapidity in the nucleon-nucleon centre-of-mass frame. The measurements are compared to the predictions from theoretical calculations based on parton distribution functions (PDFs) at next-to-leading-order. The results favour PDF calculations that include nuclear modifications and provide constraints on the nuclear PDF global fits.
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