First Measurement of Λc Baryon Production in Au+Au Collisions at sNN =200 GeV

We report on the first measurement of the charmed baryon Λc± production at midrapidity (|y|<1) in Au+Au collisions at sNN=200 GeV collected by the STAR experiment at the Relativistic Heavy Ion Collider. The Λc/D0 [denoting (Λc++Λc-)/(D0+D&macr;0)] yield ratio is measured to be 1.08±0.16 (stat)±0.26 (sys) in the 0%-20% most central Au+Au collisions for the transverse momentum (pT) range 3<pT<6 GeV/c. This is significantly larger than the pythia model calculations for p+p collisions. The measured Λc/D0 ratio, as a function of pT 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 Λc/D0 ratio.