$J/ψ$ and $η_c$ in the Deconfined Plasma from Lattice QCD

TL;DR

Analyzing correlation functions of charmonia at finite temperature (T) on 32(3)x(32-96) anisotropic lattices by the maximum entropy method (MEM) finds that J/psi and eta(c) survive as distinct resonances in the plasma even up to T approximately 1.6T(c), which suggests that the deconfined plasma is nonperturbative enough to hold heavy-quark bound states.

Abstract

Analyzing correlation functions of charmonia at finite temperature ($T$) on $32^3\times(32-96)$ anisotropic lattices by the maximum entropy method (MEM), we find that $J/ψ$ and $η_c$ survive as distinct resonances in the plasma even up to $T \simeq 1.6 T_c$ and that they eventually dissociate between $1.6 T_c$ and $1.9 T_c$ ($T_c$ is the critical temperature of deconfinement). This suggests that the deconfined plasma is non-perturbative enough to hold heavy-quark bound states. The importance of having sufficient number of temporal data points in MEM analyses is also emphasized.

Figures (4)

• Figure 1: Spectral functions for $J/\psi$ (a) for $T/T_c=0.78, 1.38$, and $1.62$ (b) for $T/T_c=1.87$ and $2.33$.
• Figure 2: Spectral functions for $\eta_c$ (a) for $T/T_c=0.78, 1.38$, and $1.62$ (b) for $T/T_c=1.87$ and $2.33$.
• Figure 3: Spectral functions for $J/\psi$ with MEM errors (a) for $T/T_c=1.62$ (b) $T/T_c=1.87$.
• Figure 4: Comparison of the SPF for $J/\psi$ (a) for $N_{\rm data} = 34$ and 39 with $N_{\tau}=46$$(T/T_c=1.62)$ (b) for $N_{\rm data} =26$ and 33 with $N_{\tau}=40$$(T/T_c=1.87)$.