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 (pro duced 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 sam ple 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 measure ments 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 frag mentation 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 mea surements 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 mea surements, 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 pre dicted by perturbative QCD calculations.