# Studies of a thermally averaged p-wave Sommerfeld factor

## TL;DR

This paper examines how attractive SU(3) gauge interactions affect the thermal p-wave annihilation rate of heavy particles, revealing significant enhancement factors up to 100 through theoretical and lattice methods.

## Contribution

It provides the first detailed analysis of thermally averaged p-wave Sommerfeld factors including bound state effects for SU(3) interactions.

## Key findings

- Bound states significantly enhance annihilation rates.
- Enhancement factors can reach up to approximately 100.
- Both perturbative and lattice methods agree on the estimates.

## Abstract

Thermal pair annihilation of heavy particles, such as dark matter or its co-annihilation partners, can be strongly influenced by attractive interactions. We investigate the case that pair annihilation proceeds through a velocity-suppressed $p$-wave operator, in the presence of an SU(3) gauge force. Making use of a non-relativistic effective theory, the thermal average of the pair-annihilation rate is estimated both through a resummed perturbative computation and through lattice simulation, in the range $M/T \sim 10 ... 30$. Bound states contribute to the annihilation process and enhancement factors of up to $\sim 100$ can be found.