First measurement of $\Lambda_c$ baryon production in Au+Au collisions at $\sqrt{s_{\rm NN}}$ = 200 GeV

TL;DR

This paper presents the first measurement of $\Lambda_c$ baryon production in gold-gold collisions at 200 GeV, revealing a higher baryon-to-meson ratio than in proton-proton collisions, consistent with coalescence models.

Contribution

It provides the first experimental data on $\Lambda_c$ production in heavy-ion collisions at RHIC energies, highlighting the role of coalescence in charm baryon formation.

Findings

$\Lambda_c$/$D^0$ ratio is about 1.08 in central Au+Au collisions.

The ratio exceeds PYTHIA $p+p$ collision predictions.

Results support coalescence hadronization models for charm baryons.

Abstract

We report on the first measurement of the charmed baryon $\Lambda_c^{\pm}$ production at midrapidity ($|y|$ $<$ 1) in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV collected by the STAR experiment at the Relativistic Heavy Ion Collider. The $\Lambda_c$/$D^0$ (denoting ($\Lambda_c^++\Lambda_c^-$)/($D^0+\bar{D^0}$)) yield ratio is measured to be 1.08 $\pm$ 0.16 (stat.) $\pm$ 0.26 (sys.) in the 0--20% most central Au+Au collisions for the transverse momentum ($p_T$) range 3 $<$ $p_T$ $<$ 6 GeV/$c$. This is significantly larger than the PYTHIA model calculations for $p+p$ collisions. The measured $\Lambda_c$/$D^0$ ratio, as a function of $p_T$ and collision centrality, is comparable to the baryon-to-meson ratios for light and strange hadrons in Au+Au collisions. Model calculations including coalescence hadronization for charmed baryon and meson formation reproduce the features of our measured $\Lambda_c$/$D^0$ ratio.