Towards the Gravity Dual of Quarkonium in the Strongly Coupled QCD Plasma

TL;DR

This paper develops a holographic model for charmonium in strongly coupled QCD plasma, matching spectral data including masses and decay constants, and predicts J/psi melting at high temperature consistent with lattice results.

Contribution

It introduces a novel bottom-up holographic model for charmonium that incorporates decay constants and predicts quarkonium melting temperatures.

Findings

J/psi spectral peak melts at about 540 MeV (2.8 T_c).

Model matches experimental spectral data for charmonium.

Predicted melting temperature agrees with lattice QCD results.

Abstract

We build a "bottom-up" holographic model of charmonium by matching the essential spectral data. We argue that this data must include not only the masses but also the decay constants of the J/psi and psi' mesons. Relative to the "soft-wall" models for light mesons, such a matching requires two new features in the holographic potential: an overall upward shift as well as a narrow "dip" near the holographic boundary. We calculate the spectral function as well as the position of the complex singularities (quasinormal frequencies) of the retarded correlator of the charm current at finite temperatures. We further extend this analysis by showing that the residues associated with these singularities are given by the boundary derivative of the appropriately normalized quasinormal mode. We find that the "melting" of the J/psi spectral peak occurs at a temperature of about 540 MeV, or 2.8 T_c, in good agreement with lattice results.