Charm hadronisation measurements with the ALICE experiment

¹ Dipartimento di Fisica e Astronomia, University of Bologna
² Istituto Nazionale di Fisica Nucleare (INFN), sezione di Bologna

^* e-mail: marco.giacalone@bo.infn.it

Published online: 17 November 2022

Abstract

Charm quarks are produced in hard scatterings at the early stages of the hadronic collisions due to the heavy mass of the quark. The production cross section of charm can be described by pQCD calculations based on the factorisation approach. This description traditionally assumes universal fragmentation functions of charm into hadrons among different collision systems.

The ALICE experiment measured charmed-baryon production in pp collisions for different baryon species, observing a significant enhancement of the charm baryon-to-meson yield ratios, for p_T < 10–12 GeV/c, with respect to measurements performed at e⁺e⁻ and ep colliders. Measurements of charmed baryon production in pp collisions also provide a fundamental reference for heavy-ion collisions, in which an enhancement of the baryon-to-meson ratio could be due to an additional hadronisation mechanism via coalescence of charm quarks with lighter quarks in a deconfined medium.

This contribution discusses the latest measurements of charm production performed by the ALICE Collaboration in pp collisions at the LHC via D mesons, Λ_c⁺, Σ_c^0,+,++, Ξ_c^0,+, and Ω_c⁰ baryons at midrapidity at √s = 5.02 and 13 TeV. The most recent measurements of the Λ_c⁺/D⁰ ratio in Pb–Pb collisions at √s_NN = 5.02 are also presented, together with the first measurement of the charm fragmentation fraction into hadrons in pp and p–Pb collisions at the same energy.