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Title: Nuclear effects on the transverse momentum spectra of charged particles in pPb collisions at $$\sqrt{s_{_\mathrm {NN}}} =5.02$$ TeV

Transverse momentum spectra of charged particles are measured by the CMS experiment at the CERN LHC in pPb collisions at √sNN = 5.02 TeV, in the range 0.4T < 120 GeV/c and pseudorapidity |ηCM|<1.8 in the proton–nucleon center-of-mass frame. For pT < 10 GeV/c, the charged-particle production is asymmetric about ηCM=0, with smaller yield observed in the direction of the proton beam, qualitatively consistent with expectations from shadowing in nuclear parton distribution functions (nPDF). A pp reference spectrum at √s = 5.02 TeV is obtained by interpolation from previous measurements at higher and lower center-of-mass energies. The pTdistribution measured in pPb collisions shows an enhancement of charged particles with pT > 20GeV/c compared to expectations from the pp reference. As a result, the enhancement is larger than predicted by perturbative quantum chromodynamics calculations that include antishadowing modifications of nPDFs.
  1. Yerevan Physics Inst. (YerPhI), Yerevan (Armenia). et al.
Publication Date:
OSTI Identifier:
Report Number(s):
FERMILAB-PUB--15-064-CMS; CERN-PH-EP--2014-282; CMS-HIN--12-017
Journal ID: ISSN 1434-6052; arXiv eprint number arXiv:1502.05387
Grant/Contract Number:
Accepted Manuscript
Journal Name:
European physical journal. C, Particles and fields (Online)
Additional Journal Information:
Journal Name: European physical journal. C, Particles and fields (Online); Journal Volume: 75; Journal Issue: 5; Journal ID: ISSN 1434-6052
Research Org:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Contributing Orgs:
CMS Collaboration
Country of Publication:
United States
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS CMS; physics; relativistic heavy-ion collisions