Abstract
Journal of high energy physics 05(5), 220 (2021). doi:10.1007/JHEP05(2021)220
The p$_{T}$-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 $ \sqrt{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 D$^{0}$ K$^{ }$ $^{+}$, D$^{+}$ K$^{ }$ $^{+}$ $^{+}$, and $ {\mathrm{D}}_{\mathrm{s}}^{+}\to \phi {\pi}^{+}\to {\mathrm{K}}^{-}{\mathrm{K}}^{+}{\pi}^{+} $ and their charge conjugates. Compared to previous measurements in the same rapidity region, the cross sections of prompt D$^{+}$ and $ {\mathrm{D}}_{\mathrm{s}}^{+} $ mesons have an extended p$_{T}$ coverage and total uncertainties reduced by a factor ranging from 1.05 to 1.6, depending on p$_{T}$, allowing for a more precise determination of their p$_{T}$-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, f$_{s}$/(f$_{u}$ + f$_{d}$), is compatible for charm and beauty quarks and with previous measurements at different centre-of-mass energies and collision systems. The $ \mathrm{b}\overline{\mathrm{b}} $ production cross section per rapidity unit at midrapidity, estimated from non-prompt D-meson measurements, is $ \mathrm{d}{\sigma}_{\mathrm{b}\overline{\mathrm{b}}}/\mathrm{d}y\left|{}_{\left|\mathrm{y}\right|<0.5}=34.5\pm 2.4{\left(\mathrm{stat}\right)}_{-2.9}^{+4.7}\left(\mathrm{tot}.\mathrm{syst}\right)\right. $ b. It is compatible with previous measurements at the same centre-of-mass energy and with the cross section predicted by perturbative QCD calculations.
Published by SISSA, [Trieste]