CMS-PAS-HIN-21-004

CMS-PAS-HIN-21-004
Study of charm hadronization with prompt $\Lambda_c^+$ baryons in proton-proton and lead-lead collisions at $\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}=$ 5.02 TeV
CMS Collaboration
26 March 2023

Abstract: The production of prompt $\Lambda_c^+$ baryons is measured via the exclusive decay channel $\Lambda_c^+ \to \mathrm{p} \mathrm{K}^- \pi^+$ at a center-of-mass energy per nucleon pair of 5.02 TeV using 252 nb $^{-1}$ proton-proton (pp) and 0.607 nb $^{-1}$ lead-lead (PbPb) collisions collected at the CERN LHC in 2017 and 2018, respectively. The measurements are performed within the $\Lambda_c^+$ rapidity interval $\|y\| <$ 1.0 with transverse momentum ( $p_\mathrm{T}$ ) ranges of 3-30 and 6-40 $\mathrm{GeV}/c$ for pp and PbPb collisions, respectively. Compared to pp collisions scaled by the number of nucleon-nucleon interactions, the observed yields of $\Lambda_c^+$ with $p_\mathrm{T} >$ 10 GeV/ $c$ are strongly suppressed in PbPb collisions. The level of suppression depends significantly on both the collision centrality and the $p_\mathrm{T}$ of the $\Lambda_c^+$ baryon. The $\Lambda_c^+/\mathrm{D}^0$ production ratio in PbPb collisions is consistent with the result in pp collisions for $p_\mathrm{T} >$ 10 GeV/ $c$ , suggesting that the coalescence process of hadronization is not significant for PbPb collisions in the higher $p_\mathrm{T}$ region.
Links: CDS record (PDF) ; CADI line (restricted) ; These preliminary results are superseded in this paper, Submitted to JHEP. The superseded preliminary plots can be found here.

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