Bayesian study of relativistic open and hidden charm in anisotropic lattice QCD

TL;DR

This study uses relativistic lattice QCD with Bayesian spectral reconstruction to analyze how charmonium and open-charm mesons behave at finite temperature, revealing state-specific in-medium modifications and dissociations around the QCD transition.

Contribution

It is the first combined relativistic lattice QCD analysis of correlators and spectral functions for charmonium and open-charm mesons at finite temperature, employing two Bayesian methods for spectral reconstruction.

Findings

No significant in-medium modification for J/ψ and η_c around the crossover.

χ_c states show clear changes near the transition.

D mesons do not significantly modify at T_c but likely dissociate at T=352 MeV.

Abstract

We present the first combined study of correlators and spectral properties of charmonium and open-charm-mesons at finite temperature using a fully relativistic lattice QCD approach. The QCD medium is captured by second generation anisotropic 24^3xN_t lattices from the FASTSUM collaboration, including 2+1 flavors of clover discretized quarks with m_pi~380 MeV. Two Bayesian methods are deployed to reconstruct the spectral functions, the recent BR method as well as the Maximum Entropy Method with Fourier basis. We take particular care to disentangle genuine in-medium effects from method artifacts with the help of the reconstructed correlator. Consistent with the direct inspection of correlators, we observe no significant in-medium modification for J/Psi and eta_c around the crossover, while the chi_c states on the other hand show clear changes around the transition. At the highest temperature, T=352 MeV, J/Psi and eta_c also exhibit discernible changes compared to the vacuum. For D mesons around $T_c$, no significant modifications are observed, but we find clear indications that no bound state survives at the highest temperature of T=352 MeV. Above T_c we discover a significant difference between D and D* mesons, the latter being much more strongly affected by the medium.