Observation of nuclear modifications in W < sup > ± < /sup > boson production in pPb collisions at s < inf > NN < /inf > =8.16TeV
Observation of nuclear modifications in W < sup > ± < /sup > boson production in pPb collisions at s < inf > NN < /inf > =8.16TeV
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Date
2020-01-10
Authors
Sirunyan, A. M.
Tumasyan, A.
Adam, W.
Ambrogi, F.
Asilar, E.
Bergauer, T.
Brandstetter, J.
Dragicevic, M.
Erö, J.
Escalante Del Valle, A.
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Abstract
The production of W± bosons is studied in proton-lead (pPb) collisions at a nucleon-nucleon centre-of-mass energy of sNN=8.16TeV. Measurements are performed in the W±→μ±νμ channel using a data sample corresponding to an integrated luminosity of 173.4±6.1nb−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 |ηlabμ| < 2.4 and transverse momentum pTμ > 25GeV/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.
Description
Keywords
CMS,
Electroweak,
Heavy ions,
nPDF,
pPb,
W boson
Citation
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. v.800