Transverse momentum spectra of charged particles are measured by the CMS experiment at the CERN LHC in pPb collisions at root s(NN) = 5.02 TeV, in the range 0.4 < pT < 120 GeV/c and pseudorapidity |eta(CM)| < 1.8 in the proton-nucleon center-of-mass frame. For p(T) < 10 GeV/c, the charged-particle production is asymmetric about eta(CM) = 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 root s = 5.02 TeV is obtained by interpolation from previous measurements at higher and lower center-of-mass energies. The p(T) distribution measured in pPb collisions shows an enhancement of charged particles with p(T) > 20 GeV/c compared to expectations from the pp reference. The enhancement is larger than predicted by perturbative quantum chromodynamics calculations that include antishadowing modifications of nPDFs.

Nuclear effects on the transverse momentum spectra of charged particles in pPb collisions at √sNN = 5.02 TeV

GABUSI, MICHELE;RATTI, SERGIO PEPPINO;RICCARDI, CRISTINA;SALVINI, PAOLA;VITULO, PAOLO
2015-01-01

Abstract

Transverse momentum spectra of charged particles are measured by the CMS experiment at the CERN LHC in pPb collisions at root s(NN) = 5.02 TeV, in the range 0.4 < pT < 120 GeV/c and pseudorapidity |eta(CM)| < 1.8 in the proton-nucleon center-of-mass frame. For p(T) < 10 GeV/c, the charged-particle production is asymmetric about eta(CM) = 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 root s = 5.02 TeV is obtained by interpolation from previous measurements at higher and lower center-of-mass energies. The p(T) distribution measured in pPb collisions shows an enhancement of charged particles with p(T) > 20 GeV/c compared to expectations from the pp reference. The enhancement is larger than predicted by perturbative quantum chromodynamics calculations that include antishadowing modifications of nPDFs.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11571/1164639
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