Discrete R Symmetries and Domain Walls

TL;DR

This paper examines the cosmological implications of discrete R symmetries, focusing on domain wall formation, their potential problems, and mechanisms for their annihilation to ensure consistency with cosmological constraints.

Contribution

It analyzes various breaking mechanisms of discrete R symmetries and their effectiveness in preventing cosmological issues caused by domain walls.

Findings

Domain walls can be inflated away in some supersymmetry breaking schemes.

In other schemes, domain walls form after inflation and must be annihilated.

Constraints on symmetry breaking mechanisms are identified to ensure walls do not cause cosmological problems.

Abstract

Discrete R symmetries are interesting from a variety of points of view. They raise the specter, however, of domain walls, which may be cosmologically problematic. In this note, we describe some of the issues. In many schemes for supersymmetry breaking, as we explain, satisfying familiar constraints such as suppression of gravitino production, insures that the domain walls are readily inflated away. However, in others, they form after inflation. In these cases, it is necessary that they annihilate. We discuss possible breaking mechanisms for the discrete symmetries, and the constraints they must satisfy so that the walls annihilate effectively.