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 ($p_{ T}\lesssim7$ 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 $\Lambda_{ c}^{ +}/D^{ 0}$ 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 $p_{ T}\gtrsim3$ 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 $\Xi_{ c}^{ 0}$, $\Omega_{ c}^{ 0}$ 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.
Categories: hep-ph