Curvaton Decay into Baryons, anti-Baryons and Radiation

TL;DR

This paper investigates how curvaton decay affects baryon and radiation isocurvature fluctuations, showing that decay preserving baryon number can transfer initial isocurvature modes into baryon/radiation modes, with detailed analytical and numerical analysis.

Contribution

It provides a detailed analysis of baryon/radiation isocurvature transfer during curvaton decay, highlighting differences based on baryon number conservation.

Findings

If curvaton decay preserves baryon number, initial isocurvature modes transfer entirely to baryon/radiation modes.

The transfer efficiency depends on whether baryon number is conserved during decay.

Analytical and numerical calculations confirm the transfer mechanisms in different scenarios.

Abstract

This paper calculates the amount of baryon/radiation isocurvature fluctuation produced through the decay of a curvaton field. It is shown in particular that if curvaton decay preserves baryon number and the curvaton dominates the energy density at the time of decay, the initial curvaton/radiation isocurvature mode is entirely transfered into a baryon/radiation isocurvature mode. This situation is opposite to that previously studied in three fluid models of curvaton decay; this difference is related to the conservation of the pre-existing baryon asymmetry and to the efficiency of the annihilation of all baryon/anti-baryon pairs produced in the decay. We study in detail the relevant cases in which the curvaton decay preserves or not baryon number and provide analytical and numerical calculations for each situation.