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 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 D0→ K−π+, D+→ K−π+π+, and {mathrm{D}}_{mathrm{s}}^{+}to upphi {uppi}^{+}to {mathrm{K}}^{-}{mathrm{K}}^{+}{uppi}^{+} 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 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 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}yleft|{}_{left|mathrm{y}right|<0.5}=34.5pm 2.4{left(mathrm{stat}right)}_{-2.9}^{+4.7}left(mathrm{tot}.mathrm{syst}right)right. 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.
Highlights
Transition from heavy quarks to heavy-flavour hadrons [64]
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
In this paper we report an update of the measurement of prompt D+- and D+s -meson√production performed with ALICE in the rapidity interval |y| < 0.5 in pp collisions at s = 5.02 TeV [3], obtained using an improved analysis technique
Summary
The ALICE apparatus is composed of a central barrel, consisting of a set of detectors for particle reconstruction and identification at midrapidity, a forward muon spectrometer, and various forward and backward detectors for triggering and event characterisation. The V0 detector was used for triggering and event selection It is composed of two scintillator arrays, located on both sides of the nominal interaction point and covering the pseudorapidity intervals −3.7 < η < −1.7 and 2.8 < η < 5.1. Events were further selected offline in order to remove background due to the interaction between one of the beams and the residual gas present in the beam vacuum tube and other machine-induced backgrounds [68] This selection was based on the timing information of the two V0 arrays and the correlation between the number of hits and track segments in the two innermost layers of the ITS, consisting of Silicon Pixel Detectors (SPD).
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