Study of charm hadronization with prompt Λc+ baryons in proton-proton and lead-lead collisions at sNN = 5.02 TeV

The production of prompt Λ_c ⁺ baryons is measured via the exclusive decay channel Λ_c ⁺→pK⁻π⁺ at a center-of-mass energy per nucleon pair of 5.02 TeV, using proton-proton (pp) and lead-lead (PbPb) collision data collected by the CMS experiment at the CERN LHC. The pp and PbPb data were obtained in 2017 and 2018 with integrated luminosities of 252 and 0.607 nb⁻¹, respectively. The measurements are performed within the Λ_c ⁺ rapidity interval |y| < 1 with transverse momentum (p_T) ranges of 3–30 and 6–40 GeV/c for pp and PbPb collisions, respectively. Compared to the yields in pp collisions scaled by the expected number of nucleon-nucleon interactions, the observed yields of Λ_c ⁺ with p_T> 10 GeV/c are strongly suppressed in PbPb collisions. The level of suppression depends significantly on the collision centrality. The Λ_c ⁺/D⁰ production ratio is similar in PbPb and pp collisions at p_T> 10 GeV/c, suggesting that the coalescence process does not play a dominant role in prompt Λ_c ⁺ baryon production at higher p_T.