Constraining hadronization mechanisms with $\rm Λ_{\rm c}^{+}$/D$^0$ production ratios in Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV

The production of prompt $\rm \Lambda_{\rm c}^{+}$ baryons at midrapidity ($|y|<~0.5$) was measured in central (0-10%) and mid-central (30-50%) Pb-Pb collisions at the center-of-mass energy per nucleon-nucleon pair $\sqrt{s_{\rm NN}} = 5.02$ TeV with the ALICE detector. The $\rm \Lambda_{\rm c}^{+}$ production yield, the $\rm \Lambda_{\rm c}^{+}$/D$^0$ production ratio, and the $\rm \Lambda_{\rm c}^{+}$ nuclear modification factor $R_{\rm AA}$ are reported. The results are more precise and more differential in transverse momentum ($p_{\rm T}$) and centrality with respect to previous measurements. The $\rm \Lambda_{\rm c}^{+}$/D$^0$ ratio, which is enhanced with respect to the pp measurement for $4<~ p_{\rm T} <~ 8$ GeV/$c$, is described by theoretical calculations that model the charm-quark transport in the quark-gluon plasma and include hadronization via both coalescence and fragmentation mechanisms.

 

Submitted to: PRL
e-Print: arXiv:2112.08156 | PDF | inSPIRE
Figure group

Figure 1

Left: \pt-differential production yields of prompt \Lc in central (0--10\%) and mid-central (30--50\%) \PbPb collisions at \fivenn. Right: \LcD ratio in central and mid-central \PbPb collisions at \fivenn compared with the results obtained from \pp collisions~.

Figure 2

The nuclear modification factor of prompt \Lc as a function of \pt in central (0--10\%) and mid-central (30--50\%) \PbPb collisions at \fivenn. The normalization uncertainties are shown as boxes around unity.

Figure 3

The \LcD yield ratio as a function of \pt in 0--10\% (left) and 30--50\% (middle) \PbPb and \pp (right) collisions at \fivenn compared with predictions of different theoretical calculations~.

Figure 4

Invariant mass ($M$) distributions of \LctopKzerosfull candidates and charge conjugates in different \pt intervals in central (0--10\%; top) and mid-central (30--50\%; bottom) \PbPb collisions at \fivenn. The blue solid lines show the total fit functions and the red dashed lines are the combinatorial-background terms. The values of the mean ($\mu$) and the width ($\sigma$) of the signal peak are reported together with the signal counts ($S$) and the signal-over-background ratio ($S/B$) in the mass interval ($\mu-3\sigma,\mu+3\sigma$).