Quarkonium dissociation by anisotropy

TL;DR

This paper calculates how anisotropy in a strongly coupled plasma affects quarkonium dissociation, revealing critical anisotropy levels and velocity limits that influence meson stability.

Contribution

It provides the first comprehensive analysis of quarkonium screening lengths in an anisotropic plasma using holography, considering arbitrary velocities and orientations.

Findings

Anisotropic screening length varies with temperature and entropy density.

Mesons dissociate at a critical anisotropy even at zero temperature.

Ultra-relativistic screening length scales as (1-v^2)^{1/2}.

Abstract

We compute the screening length for quarkonium mesons moving through an anisotropic, strongly coupled N=4 super Yang-Mills plasma by means of its gravity dual. We present the results for arbitrary velocities and orientations of the mesons, as well as for arbitrary values of the anisotropy. The anisotropic screening length can be larger or smaller than the isotropic one, and this depends on whether the comparison is made at equal temperatures or at equal entropy densities. For generic motion we find that: (i) mesons dissociate above a certain critical value of the anisotropy, even at zero temperature; (ii) there is a limiting velocity for mesons in the plasma, even at zero temperature; (iii) in the ultra-relativistic limit the screening length scales as $(1-v^2)^\epsilon$ with \epsilon =1/2, in contrast with the isotropic result \epsilon =1/4.