Q-balls in flat potentials

TL;DR

This paper analyzes the stability of Q-balls in flat potentials within scalar field theories, demonstrating conditions for classical and absolute stability in gravity-mediated and gauge-mediated models.

Contribution

It provides a detailed stability analysis of Q-balls in flat potentials, identifying conditions for classical and absolute stability in different mediation scenarios.

Findings

Q-matter in gravity-mediated potentials can be stable if nonrenormalisable coupling is small.

All 3D Q-ball configurations are classically stable against linear fluctuations.

Gauge-mediated Q-balls are absolutely stable in the thin-wall limit but unstable in the thick-wall limit.

Abstract

We study the classical and absolute stability of Q-balls in scalar field theories with flat potentials arising in both gravity-mediated and gauge-mediated models. We show that the associated Q-matter formed in gravity-mediated potentials can be stable against decay into their own free particles as long as the coupling constant of the nonrenormalisable term is small, and that all of the possible three-dimensional Q-ball configurations are classically stable against linear fluctuations. Three-dimensional gauge-mediated Q-balls can be absolutely stable in the "thin-wall-like" limit, but are completely unstable in the "thick-wall" limit.