Abstract
The study of charm quark hadrons is an important probe into the hadronization of heavy quarks. More specifically, we present results on the production of Λc baryon, the nuclear modification factors (RAA), and the Λc/D0 yield ratios at √SNN = 5.02 TeV in proton-proton (pp) collisions and in different centrality regions in lead-lead (PbPb) collisions, using data recorded with the CMS detector in 2017 and 2018, respectively. The reported RAA for Λc provides useful information regarding the energy loss mechanism and the hadronization processes of charm quark in the quark-gluon plasma. The transverse momentum (pT) dependence of the RAA is similar to that of other charm and beauty hadrons but with its minimum shifted towards higher pT. Comparing the Λc/D0 production ratio in pp and PbPb collisions suggests that coalescence as a hadronization process is not significant for pT > 10 GeV/c. The ratio becomes comparable to the measurements in e+e− collisions for pT > 30 GeV/c. We also present results of the Λc baryon and D0 meson production and their ratios in proton-lead (pPb) collisions at √SNN = 8.16 TeV as a function of pT and final-state multiplicity using the data recorded by the CMS experiment in 2016. We do not observe significant multiplicity dependence for the baryon over meson ratio for charm hadrons. Based on a previous study, the difference between the results from charm quarks and those from light quarks suggests coalescence processes for heavy quarks do not increase further with multiplicity, unlike light quarks.