Supersymmetric D-term Inflation, Reheating and Affleck-Dine Baryogenesis

TL;DR

The paper analyzes supersymmetric D-term inflation models driven by a Fayet-Iliopoulos term, focusing on achieving a sufficiently flat inflaton potential, a reheating history compatible with gravitino constraints, and successful Affleck-Dine baryogenesis. It shows that higher-dimension operators and kinetic mixing threaten the flatness unless forbidden by an appropriate symmetry, often requiring an R-symmetry or discrete gauge symmetry. Reheating proceeds via two stages: an initial ultra-high reheat temperature from ψ_- decays followed by a lower-temperature S decay that dilutes gravitinos, with the latter depending on higher-dimension couplings that can be arranged to satisfy constraints. Affleck-Dine baryogenesis can be implemented in these scenarios, with the baryon asymmetry sensitive to the lifting order n of MSSM flat directions and to the post-inflationary thermal history, particularly the second-stage reheat temperature. Overall, a large subset of D-term inflation models can accommodate a very flat potential, gravitino-safe reheating, and viable baryogenesis, given suitable symmetry protection and decay-channel structure.

Abstract

The phenomenology of supersymmetric models of inflation, where the inflationary vacuum energy is dominated by D-terms of a U(1), is investigated. Particular attention is paid to the questions of how to arrange for sufficient e-folds of inflation to occur, what kind of thermal history is expected after the end of inflation, and how to implement successful baryogenesis. Such models are argued to require a more restrictive symmetry structure than previously thought. In particular, it is non-trivial that the decays of the fields driving D-inflation can reheat the universe in such a way as to avoid the strong gravitino production constraints. We also show how the initial conditions for Affleck-Dine baryogenesis can arise in these models and that the simplest flat directions along which baryon number is generated can often be ruled out by the constraints coming from decoherence of the condensate in a hot environment. At the end, we find that successful reheating and baryogenesis can take place in a large subset of D-inflationary models.