Hidden-charm pentaquark states in heavy ion collisions at energies available at the CERN Large Hadron Collider

In the framework of the quark combination, we derive the yield formulas and study the yield ratios of hidden-charm pentaquark states in ultrarelativistic heavy ion collisions. We propose some interesting yield ratios which clearly exhibit the production relationships between different hidden-charm pentaquark states. We show how to employ a specific quark combination model to evaluate the yields and predict the transverse momentum ($p_T$) spectra of exotic $P_c^{+}\left(4380\right), P_c^{+}\left(4450\right)$, and their partners as pentaquark states on the basis of reproducing the yields and $p_T$ spectra of normal identified hadrons and execute the calculations in central Pb + Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV as an example.

Figure 1

(a) $p_T$ spectra of $D^0$ mesons, ${\mathrm{\Lambda }}_c^{+}$ baryons, and hidden-charm pentaquark states $P_{uudc\overline{c}}$ and $P_{uusc\overline{c}}$; (b) ratios $P_{uudc\overline{c}}/D^0$ and $P_{uusc\overline{c}}/D^0$; (c) ratios $P_{uudc\overline{c}}/{\mathrm{\Lambda }}_c^{+}$ and $P_{uusc\overline{c}}/{\mathrm{\Lambda }}_c^{+}$ at midrapidity in central Pb + Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV. Filled symbols represent the experimental data from Ref. [45], and different lines show our results. Solid lines show results under the equal $p_T$ combination scenario; dashed lines, results under the equal $v_T$ combination scenario. In (a) $p_T$ distributions of $D^0$ and $P_{uudc\overline{c}}$ are scaled by 100 and 10, respectively, for clarity.