Falsifying Pati-Salam models with LIGO

TL;DR

This paper uses LIGO gravitational wave data to constrain Pati-Salam grand unified models, providing new limits that complement collider searches and will improve with future observations.

Contribution

It is the first to constrain Pati-Salam models using gravitational wave data and phase transition requirements, expanding the methods for testing grand unified theories.

Findings

LIGO data constrains Pati-Salam models beyond collider reach

Phase transition completion imposes significant parameter constraints

Future LIGO and Einstein telescope will tighten these bounds

Abstract

We demonstrate that existing gravitational wave data from LIGO already places constraints on well motivated Pati-Salam models that allow the Standard Model to be embedded within grand unified theories. For the first time in these models we also constrain the parameter space by requiring that the phase transition completes, with the resulting constraint being competitive with the limits from LIGO data. Both constraints are complementary to the LHC constraints and can exclude scenarios that are much heavier than can be probed in colliders. Finally we show that results from future LIGO runs, and the planned Einstein telescope, will substantially increase the limits we place on the parameter space.