http://arxiv.org/abs/2212.05829
We study possible ways gravitational waves (GW) get sourced in a theory with minimal left-right symmetry breaking. First order phase transitions generically lead to gravitational waves sourced by bubble collisions, while second order phase transitions (SOPT) do not. Interesting variants on the standard classification of phase transitions occur due to the breaking of discrete parity combined with the limitation of light cone in the early Universe. If local effective potential signals SOPT or a cross over, breaking of discrete parity in conjunction with finiteness of the causal horizon leads to a \textsl{causal horizon limited} second order phase transition, which results in domain walls separating left-like and right-like domains. On the other hand for the case of usual first order phase transition (FOPT), we get the usual signal from spontaneously created bubbles, but also, as we argue from a lingering late time domain wall structure separating the two types of vacua. Thus both FOPT and putative SOPT give rise to distinct features in the spectrum of GW. The signatures are testable via experiments such as IPTA, and DECIGO and LISA. Finally we point out that a version of the left-right symmetric model which separates parity breaking from gauge symmetry breaking is also subject to domain wall formation and amenable to GW observations.
Z. Borboruah and U. Yajnik
Tue, 13 Dec 22
18/105
Comments: 36 pages, 23 total figures including subfigures