Production of single-charm hadrons by quark combination mechanism in $p$-Pb collisions at $\sqrt{s_{NN}}=5.02$ TeV

Abstract

If QGP-like medium is created in $p$-Pb collisions at extremely high collision energies, charm quarks that move in the medium can hadronize by capturing the co-moving light quark(s) or anti-quark(s) to form the charm hadrons. Using light quark $p_T$ spectra extracted from the experimental data of light-flavor hadrons and a charm quark $p_T$ spectrum that is consistent with perturbative QCD calculations, the central-rapidity data of $p_T$ spectra and the spectrum ratios for $D$ mesons in the low $p_T$ range ($p_T\lesssim 7$ GeV/$c$) in minimum-bias $p$-Pb collisions at $\sqrt{s_{NN}}=5.02$ TeV are well described by quark combination mechanism in equal-velocity combination approximation. The $\hat{I}{›}_c^{+}/D^0$ ratio in quark combination mechanism exhibits the typical increase-peak-decrease behavior as the function of $p_T$, and the shape of the ratio for $p_T\gtrsim 3$ GeV/$c$ is in agreement with the data of ALICE collaboration in central rapidity region $-0.96<y<0.04$ and the preliminary data of LHCb collaboration in forward rapidity region $1.5<y<4.0$. The global production of single-charm baryons is quantified using the data and the possible enhancement (relative to light flavor baryons) is discussed. The $p_T$ spectra of $\hat{I}{ž}_c^0$, $\hat{I}{\text{c◯}}_c^0$ in minimum-bias events and those of single-charm hadrons in high-multiplicity event classes are predicted, which serves as the further test of the possible change of the hadronization characteristic for low $p_T$ charm quarks in the small system created in $p$-Pb collisions at LHC energies.

15 pages, 8 figures