Spontaneously broken parity and consistent cosmology with transitory domain walls

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 a radiation dominated era, during a 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 MR 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 constrained than another admitting a gauge singlet. © 2010 The American Physical Society.