Charm fragmentation fractions and c(c)over-bar cross section in p-Pb collisions at √sNN=5.02TeV

Abstract

The total charm-quark production cross section per unit of rapidity d sigma(c (c) over bar)/dy, and the fragmentation fractions of charm quarks to different charm-hadron species f(c -> h(c)), are measured for the first time in p-Pb collisions at root s(NN)=5.02 TeV at midrapidity (-0.96 < y < 0.04 in the centre-of-mass frame) using data collected by ALICE at the CERN LHC. The results are obtained based on all the available measurements of prompt production of ground-state charm-hadron species: D-0, D+, D-s(+), and J/psi mesons, and Lambda(+)(c) and Xi(0)(c) baryons. The resulting cross section is d sigma(c (c) over bar)/dy=219.6 +/- 6.3 (stat.)(-11.8)(+10.5) (syst.)(-2.9)(+8.3) (extr.) +/- 5.4 (BR) +/- 4.6 (lumi.) +/- 19.5 (rapidity shape)+15.0 (Omega(0)(c)) mb, which is consistent with a binary scaling of pQCD calculations from pp collisions. The measured fragmentation fractions are compatible with those measured in pp collisions at root s=5.02 and 13 TeV, showing an increase in the relative production rates of charm baryons with respect to charm mesons in pp and p-Pb collisions compared with e(+)e(-) and e(-)p collisions. The p(T)-integrated nuclear modification factor of charm quarks, R-pPb(c (c) over bar)=0.91 +/- 0.04 (stat.)(-0.09)(+0.08) (syst.)(-0.03)(+0.0) (5)(extr.) +/- 0.03 (lumi.), is found to be consistent with unity and with theoretical predictions including nuclear modifications of the parton distribution functions.