Falsifying Pati-Salam models with LIGO

We demonstrate that existing gravitational wave data from LIGO already places constraints on wellmotivated 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.