Multi-Field Q-balls with Real Scalars

TL;DR

This paper investigates multi-field Q-balls involving real scalar fields, analyzing conditions for their stability and existence, especially focusing on the effects of uncharged fields and the mass of real scalars.

Contribution

It derives sufficient conditions for thick-wall solutions in multi-field Q-balls and discusses stability criteria related to the mass of real scalar fields.

Findings

Uncharged fields can contribute without destabilizing Q-balls.

Massive real scalars require a minimum charge for stability.

Conditions for thick-wall solutions are established.

Abstract

Multi-field Q-balls, in which some, but not all, of the constituent fields are real scalars, are studied. Uncharged fields may classically contribute to Q-balls provided that their effect is to not destabilise the resulting object. The thin-wall limit is reviewed based on existing literature. Sufficient conditions for the theories that can plausibly contain thick-wall solutions are derived. Necessary conditions require a detailed numerical analysis, outside the scope of this work. These conditions show that when the additional real scalars are massive, a minimum charge must accumulate in order to render the Q-ball energetically stable.