Quasinormal modes and dispersion relations for quarkonium in a plasma

TL;DR

This paper uses holography to analyze quasinormal modes and dispersion relations of quarkonium states in a plasma, revealing how their thermal mass, width, and motion depend on temperature and momentum.

Contribution

It presents the first holographic calculation of quasinormal modes for charmonium and bottomonium, including their dispersion relations in a thermal medium.

Findings

Quasinormal mode frequencies decrease with temperature, indicating meson dissociation.

Thermal widths increase with temperature, reflecting meson decay in plasma.

Dispersion relations show how meson properties depend on momentum in the medium.

Abstract

Recent investigations show that the thermal spectral function of heavy $ {b \bar b } $ and $ {c \bar c} $ vector mesons can be described using holography. These studies consider a bottom up model that captures the heavy flavour spectroscopy of masses and decay constants in the vacuum and is consistently extended to finite temperature. The corresponding spectral functions provide a picture of the dissociation process in terms of the decrease of the quasi-state peaks with temperature. Another related tool that provides important information about the thermal behaviour is the analysis of the quasinormal modes. They are field solutions in a curved background assumed to represent, in gauge/gravity duality, quasi-particle states in a thermal medium. The associated complex frequencies are related to the thermal mass and width. We present here the calculation of quasinormal modes for charmonium and bottomonium using the holographic approach. The temperature dependence of mass and thermal width are investigated. Solutions corresponding to heavy mesons moving into the plasma are also studied. They provide the dependence of the real and imaginary parts of the frequency with the quasi-particle momenta, the so called dispersion relations.