Measurement of beauty and charm production in pp collisions at √s = 5.02 TeV via non-prompt and prompt D mesons

Abstract

The pT-differential production cross sections of prompt and non-prompt (produced in beauty-hadron decays) D mesons were measured by the ALICE experiment at midrapidity (|y|<0.5) in proton--proton collisions at s√=5.02 TeV. The data sample used in the analysis corresponds to an integrated luminosity of (19.3±0.4) nb−1. D mesons were reconstructed from their decays D0→K−π+, D+→K−π+π+, and D+s→ϕπ+→K−K+π+ and their charge conjugates. Compared to previous measurements in the same rapidity region, the cross sections of prompt D+ and D+s mesons have an extended pT coverage and total uncertainties reduced by a factor ranging from 1.05 to 1.6, depending on pT, allowing for a more precise determination of their pT-integrated cross sections. The results are well described by perturbative QCD calculations. The fragmentation fraction of heavy quarks to strange mesons divided by the one to non-strange mesons, fs/(fu+fd), is compatible for charm and beauty quarks and with previous measurements at different centre-of-mass energies and collision systems. The bb⎯⎯⎯ production cross section per rapidity unit at midrapidity, estimated from non-prompt D-meson measurements, is dσbb⎯⎯⎯/dy||y|<0.5=34.5±2.4(stat.)+4.7−2.9(tot.syst.) μb. It is compatible with previous measurements at the same centre-of-mass energy and with the cross section predicted by perturbative QCD calculations.