Unified description of charmonium suppression in a quark-gluon plasma medium at RHIC and LHC energies

Recent experimental and theoretical studies suggest that the quarkonium suppression in a thermal QCD medium created in heavy ion collisions is a complex interplay of various physical processes. In this article we put together most of these processes in a unified way to calculate the charmonium survival probability (nuclear modification factor) at energies available at Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) experiments. We include shadowing as the dominant cold-nuclear-matter effect. Further, gluonic dissociation and collision damping are included, which provide width to the spectral function of charmonia in a thermal medium and cause the dissociation of charmonium along with the usual color screening. We include color screening by using our recently proposed modified Chu–Matsui model. Furthermore, we incorporate the recombination of uncorrelated charm and anticharm quarks for the regeneration of charmonium over the entire temporal evolution of the QGP medium. Finally, we do a feed-down correction from the excited states to calculate the survival probability of charmonium. We find that our unified model suitably and simultaneously describes the experimental nuclear modification data of $J/\psi$ at RHIC and LHC.

Figure 1

Variation of total dissociation width with temperature along with its components, i.e., gluonic dissociation width and width due to collisional damping.

Figure 2

Variation of gluonic-dissociation cross section of $J/\psi$ with respect to gluon energy $E_g$ at $T=0.170$ GeV and $T=0.300$ GeV.

Figure 3

Variation of recombination reactivity with respect to temperature at RHIC ($\sqrt{s_{NN}}=200$ GeV) and at LHC ($\sqrt{s_{NN}}=2.76$ TeV).

Figure 4

Survival probability ($S_p$) of $J/\psi$ in a QGP medium versus $N_{\text{part}}$ including gluonic dissociation (GD) and collisional damping (CD) at RHIC energies with and without shadowing effect (S).

Figure 5

Survival probability versus $N_{\text{part}}$ with gluonic dissociation (GD) and collisional damping (CD) along with color screening (CS) at RHIC energies with and without shadowing effect (S).

Figure 6

Same as Fig. 5 but the recombination effect (R) is also included. Only recombination (R) is also shown here.

Figure 7

Same as Fig. 6 but feed-down (FD) due to higher resonances; namely, ${\chi }_c$ and ${\psi }^{{}^{\prime }}$, is also included.

Figure 8

Survival probability ($S_p$) of $J/\psi$ in QGP medium versus $N_{\text{part}}$ including gluonic dissociation (GD) and collisional damping (CD) at LHC energies with and without shadowing effect (S).

Figure 9

Survival probability versus $N_{\text{part}}$ with gluonic dissociation (GD) and collisional damping (CD) along with color screening (CS) at LHC energies with and without shadowing effect (S).

Figure 10

Same as Fig. 9 but recombination effect (R) is also included. Only recombination (R) is also shown here.

Figure 11

Same as Fig. 10 but feed-down (FD) due to higher resonances; namely, ${\chi }_c$ and ${\psi }^{{}^{\prime }}$ are also included.