Observation of nuclear modifications in W$^\pm$ boson production in pPb collisions at $\sqrts_\mathrmNN =$ 8.16 TeV
Journal
Phys. Lett. B
Journal Volume
800
Pages
135048
Date Issued
2020
Author(s)
Abstract
The production of W bosons is studied in proton-lead (pPb) collisions at a nucleon-nucleon centreof-mass energy of s NN = 8.16 TeV. Measurements are performed in the W channel using a data sample corresponding to an integrated luminosity of 173.4 6.1 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 | lab | 25 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.
Type
journal article