Multiplicity dependence of charged pion, kaon, and (anti)proton production at large transverse momentum in p-Pb collisions at \mathbf{\sqrt{{\textit s}_{\rm NN}}} = 5.02 TeV
Abstract
The production of charged pions, kaons and (anti)protons has been measured at mid-rapidity (-0.5 < y < 0
) in p-Pb collisions at \sqrt{s_{\rm NN}}=5.02
TeV using the ALICE detector at the LHC. Exploiting particle identification capabilities at high transverse momentum (p_{\rm T}
), the previously published p_{\rm T}
spectra have been extended to include measurements up to 20 GeV/c
for seven event multiplicity classes. The p_{\rm T}
spectra for pp collisions at \sqrt{s}=7
TeV, needed to interpolate a pp reference spectrum, have also been extended up to 20 GeV/c
to measure the nuclear modification factor (R_{\rm pPb}
) in non-single diffractive p-Pb collisions. At intermediate transverse momentum (2 < p_{\rm T} < 10
\,GeV/c
) the proton-to-pion ratio increases with multiplicity in p-Pb collisions, a similar effect is not present in the kaon-to-pion ratio. The p_{\rm T}
dependent structure of such increase is qualitatively similar to those observed in pp and heavy-ion collisions. At high p_{\rm T}
(>10
GeV/c
), the particle ratios are consistent with those reported for pp and Pb-Pb collisions at the LHC energies. At intermediate p_{\rm T}
the (anti)proton R_{\rm pPb}
shows a Cronin-like enhancement, while pions and kaons show little or no nuclear modification. At high p_{\rm T}
the charged pion, kaon and (anti)proton R_{\rm pPb}
are consistent with unity within statistical and systematic uncertainties.