학술논문
Charm production and fragmentation fractions at midrapidity in pp collisions at s = 13 TeV
Document Type
Original Paper
Author
Source
Journal of High Energy Physics. 2023(12)
Subject
Language
English
ISSN
1029-8479
Abstract
Abstract: Measurements of the production cross sections of prompt D0 , D+ , D*+ , Ds+Λc+Ξc+sΛc+Ξc+cc¯Ds+Λc+Ξc0Ξc+Ξc+Σc0,++cc¯, Ds+Λc+Ξc+sΛc+Ξc+cc¯Ds+Λc+Ξc0Ξc+Ξc+Σc0,++cc¯, and Ds+Λc+Ξc+sΛc+Ξc+cc¯Ds+Λc+Ξc0Ξc+Ξc+Σc0,++cc¯ charm hadrons at midrapidity in proton-proton collisions at Ds+Λc+Ξc+sΛc+Ξc+cc¯Ds+Λc+Ξc0Ξc+Ξc+Σc0,++cc¯ = 13 TeV with the ALICE detector are presented. The D-meson cross sections as a function of transverse momentum (pT ) are provided with improved precision and granularity. The ratios of pT -differential meson production cross sections based on this publication and on measurements at different rapidity and collision energy provide a constraint on gluon parton distribution functions at low values of Bjorken-x (10−5 –10−4 ). The measurements of Ds+Λc+Ξc+sΛc+Ξc+cc¯Ds+Λc+Ξc0Ξc+Ξc+Σc0,++cc¯ (Ds+Λc+Ξc+sΛc+Ξc+cc¯Ds+Λc+Ξc0Ξc+Ξc+Σc0,++cc¯) baryon production extend the measured pT intervals down to pT = 0(3) GeV/c. These measurements are used to determine the charm-quark fragmentation fractions and the Ds+Λc+Ξc+sΛc+Ξc+cc¯Ds+Λc+Ξc0Ξc+Ξc+Σc0,++cc¯ production cross section at midrapidity (|y| < 0.5) based on the sum of the cross sections of the weakly-decaying ground-state charm hadrons D0 , D+ , Ds+Λc+Ξc+sΛc+Ξc+cc¯Ds+Λc+Ξc0Ξc+Ξc+Σc0,++cc¯, Ds+Λc+Ξc+sΛc+Ξc+cc¯Ds+Λc+Ξc0Ξc+Ξc+Σc0,++cc¯, Ds+Λc+Ξc+sΛc+Ξc+cc¯Ds+Λc+Ξc0Ξc+Ξc+Σc0,++cc¯ and, for the first time, Ds+Λc+Ξc+sΛc+Ξc+cc¯Ds+Λc+Ξc0Ξc+Ξc+Σc0,++cc¯, and of the strongly-decaying J/ψ mesons. The first measurements of Ds+Λc+Ξc+sΛc+Ξc+cc¯Ds+Λc+Ξc0Ξc+Ξc+Σc0,++cc¯ and Ds+Λc+Ξc+sΛc+Ξc+cc¯Ds+Λc+Ξc0Ξc+Ξc+Σc0,++cc¯ fragmentation fractions at midrapidity are also reported. A significantly larger fraction of charm quarks hadronising to baryons is found compared to e+ e− and ep collisions. The Ds+Λc+Ξc+sΛc+Ξc+cc¯Ds+Λc+Ξc0Ξc+Ξc+Σc0,++cc¯ production cross section at midrapidity is found to be at the upper bound of state-of-the-art perturbative QCD calculations.