Spontaneously broken parity and consistent cosmology with transitory domain walls

TL;DR

This paper investigates how Planck scale suppressed effects can eliminate domain walls formed in theories with spontaneously broken parity, ensuring compatibility with cosmology across different evolution scenarios.

Contribution

It analyzes specific evolution scenarios and identifies conditions under which Planck scale effects can safely remove domain walls in parity-breaking models.

Findings

Planck scale suppressed operators can remove domain walls in certain scenarios.

Constraints on parity breaking scale depend on the evolution scenario.

Models with gauge singlets are less constrained than those without.

Abstract

Domain wall structure which may form in theories with spontaneously broken parity is generically in conflict with standard cosmology. It has been argued that Planck scale suppressed effects can be sufficient for removing such domain walls. We study this possibility for three specific evolution scenarios for the domain walls, with evolution during radiation dominated era, during matter dominated era, and that accompanied by weak inflation. We determine the operators permitted by the supergravity formalism and find that the field content introduced to achieve desired spontaneous parity breaking makes possible Planck scale suppressed terms which can potentially remove the domain walls safely. However, the parity breaking scale, equivalently the majorana mass scale $M_R$ of the right handed neutrino, does get constrained in some of the cases, notably for the matter dominated evolution case which would be generic to string theory inspired models giving rise to moduli fields. One left-right symmetric model with only triplets and bidoublets is found to be more constrainted than another admitting a gauge singlet.