Baryogenesis from the Inflaton Field

TL;DR

This paper proposes a novel mechanism where the inflaton field, modeled as a complex scalar with a weakly broken symmetry, can generate the universe's baryon asymmetry during inflation, aligning with observational data.

Contribution

It introduces a new variant of the Affleck-Dine mechanism involving the inflaton, linking baryogenesis directly to inflationary dynamics and providing potential observational signatures.

Findings

Inflaton can produce conserved particle number during inflation

Decay of inflaton can generate baryons

Predicted isocurvature fluctuations are near current observational limits

Abstract

In this letter we show that the inflaton can generate the cosmological baryon asymmetry. We take the inflaton to be a complex scalar field with a weakly broken global symmetry and develop a new variant on the Affleck-Dine mechanism. The inflationary phase is driven by a quadratic potential whose amplitude of B-modes is in agreement with BICEP2 data. We show that a conserved particle number is produced in the latter stage of inflation, which can later decay to baryons. We present promising embeddings in particle physics, including the use of high dimension operators for decay or using a colored inflaton. We also point out observational consequences, including a prediction of isocurvature fluctuations, whose amplitude is just below current limits, and a possible large scale dipole.