Observation of nuclear modifications in W± boson production in pPb collisions at
The production of W$$^\pm$$ bosons is studied in proton-lead (pPb) collisions at a nucleon-nucleon centre-of-mass energy of $$\sqrt{s_\mathrm{NN}} =$$ 8.16 TeV. Measurements are performed in the W$$^\pm \to \mu^\pm\nu_\mu$$ channel using a data sample corresponding to an integrated luminosity of 173.4 $$\pm$$ 8.7 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 $$|\eta^\mu_\mathrm{lab}| <$$ 2.4 and transverse momentum $$p_\mathrm{T}^\mu >$$ 25 GeV/$$c$$. The W$$^\pm$$ boson differential cross sections, muon charge asymmetry, and the ratios of W$$^\pm$$ 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. Finally, the results favour PDF calculations that include nuclear modifications and provide constraints on the nuclear PDF global fits.
- Research Organization:
- Univ. of Colorado, Boulder, CO (United States); Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), High Energy Physics (HEP)
- Contributing Organization:
- The CMS Collaboration
- Grant/Contract Number:
- SC0010005; AC02-07CH11359; AC02-05CH11231
- OSTI ID:
- 1572137
- Alternate ID(s):
- OSTI ID: 1515055; OSTI ID: 1598537; OSTI ID: 1603596
- Report Number(s):
- FERMILAB-PUB-19-228-CMS; arXiv:1905.01486; CMS-HIN-17-007; CERN-EP-2018-283; TRN: US2103306
- Journal Information:
- Physics Letters. B, Vol. 800, Issue C; ISSN 0370-2693
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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