Speaker
Description
Charm quarks are a powerful probe of the Quark-Gluon Plasma (QGP) created in high-energy heavy-ion collisions. They are produced in hard scattering processes on a timescale shorter than the QGP formation time and experience the whole system evolution. There have been extensive researches regarding the production of charm mesons, such as ${\rm D}^0$, ${\rm D}^+$D+, ${\rm D}^{*+}$, in heavy-ion collisions to investigate the interactions of charm quarks with the QGP constituents and the transport properties of the medium. The measurement of charm-baryon production, and in particular the baryon-to-meson ratios, provide unique information on hadronisation mechanisms, constraining the role of coalescence and testing the predicted presence of diquark states in the QGP.
Measurements of charm-baryon production in pp and p–Pb collisions are also essential to establish a baseline for Pb–Pb collisions. The measurements in pp collisions provide critical tests of pQCD calculations and models of charm hadronisation in vacuum; the measurements in p–Pb collisions are useful to study cold nuclear matter effects and the possible evolution with charged-particle multiplicity of the modification of charm hadronisation.
In this talk, ALICE results of charm-baryon measurements in pp, p-Pb, and Pb-Pb collisions are presented. The $p_{\rm T}$-differential cross sections of $\Lambda^+_{\rm c}$ -baryon production in pp collisions at $\sqrt{s}$ = 7 TeV and, for the first time, at $\sqrt{s}$ = 5.02 TeV are reported, along with the results in p–Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV. The $p_{\rm T}$-differential cross section times branching ratio of the $\Xi^0_{\rm c}$ baryon measured in the decay channel $\Xi^0_{\rm c} \rightarrow e^+ \Xi^- \nu_e$ in pp collisions is also discussed. Finally, the first measurement of the $\Lambda^+_{\rm c}$ production in Pb–Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV is shown.
