Thermal width and quarkonium dissociation by inelastic parton scattering

TL;DR

This paper investigates quarkonium dissociation mechanisms in a hot medium, deriving cross sections and decay widths using effective field theory, and compares inelastic parton scattering with gluo-dissociation at different temperature regimes.

Contribution

It provides a systematic derivation of dissociation cross sections and widths at finite temperature, including bound state effects and next-to-leading order corrections, within an effective field theory framework.

Findings

Inelastic parton scattering dominates at high temperatures with Debye mass > binding energy.

Derived convolution formula relates dissociation cross section and thermal decay width.

Calculated gluo-dissociation cross section and width at next-to-leading order.

Abstract

In a weak-coupling effective field theory framework we study quarkonium dissociation induced by inelastic scattering with partons in the medium. This is the dominant dissociation process for temperatures such that the Debye mass is larger than the binding energy. We evaluate the dissociation cross section and the corresponding thermal decay width. At leading order we derive a convolution formula relating the two, which is consistent with the optical theorem and QCD at finite temperature. Bound state effects are systematically included. They add contributions to the cross section and width that are beyond a quasi-free approximation, whose validity is critically reviewed. For temperatures such that the Debye mass is smaller than the binding energy, the dominant dissociation mechanism is gluo-dissociation consisting in quarkonium dissociation induced by the absorbtion of a gluon from the medium. We calculate the gluo-dissociation cross section and width at next-to-leading-order accuracy.