Tracking Down the Route to the SM with Inflation and Gravitational Waves

Abstract

We explore supersymmetric SO(10) models predicting observable proton decay and various topological defects which produce different shapes and strengths of gravitational wave backgrounds depending on the scales of intermediate breaking and inflation as well. We compare these to their non-supersymmetric counterparts. By identifying the scales at which gravitational signals appear, we would be able to track down a particular breaking chain and discern if it has a supersymmetric origin or not. It will be also useful to see the combined effect of all possible topological defects and first order phase transition for a realistic breaking chain. For this, we work out specific examples in which the grand unification and relevant intermediate scales are calculable explicitly.

Detection of early-universe gravitational-wave signatures and fundamental physics

“…More generally, GUT symmetry breaking chains more often than not allow for observable signals from some set of defects [50]. 2 Searches for proton decay provide a complimentary probe of symmetry breaking chains, as chains that allow for proton decay can be chains that do not predict strings [373,374]. Furthermore, there has been a growing interest in GWs from global/axion topological defects due to the close connection to axion or axion-like (ALP) dark matter physics [323,337,348,349,375,376]: when PQ symmetry breaking occurs after inflation, these topological defects are an indispensable companion of axion particles.…”