Detectable Gravitational Wave Signals from Affleck-Dine Baryogenesis

TL;DR

This paper explores how Affleck-Dine baryogenesis can produce detectable gravitational wave signals through the evolution and decay of Q-balls, offering a potential observational test for this baryogenesis mechanism.

Contribution

It demonstrates that Q-ball dynamics in Affleck-Dine baryogenesis generate distinctive gravitational wave signatures within the sensitivity range of future detectors.

Findings

Q-balls cause an early matter domination epoch enhancing gravitational waves.

Rapid decay of Q-balls produces a sharp peak in the gravitational wave spectrum.

Predicted signals are within the detection range of Einstein Telescope and Decigo.

Abstract

In Affleck-Dine baryogenesis, the observed baryon asymmetry of the Universe is generated through the evolution of the vacuum expectation value (VEV) of a scalar condensate. This scalar condensate generically fragments into non-topological solitons (Q-balls). If they are sufficiently long-lived, they lead to an early matter domination epoch, which enhances the primordial gravitational wave signal for modes that enter the horizon during this epoch. The sudden decay of the Q-balls into fermions results in a rapid transition from matter to radiation domination, producing a sharp peak in the gravitational wave power spectrum. Avoiding the problem of gravitino over-abundance favours scenarios where the peak frequency of the resonance is within the range of the Einstein Telescope and/or Decigo. Therefore, we show this scenario provides an observable signal, providing a mechanism to test Affleck-Dine baryogenesis.