Constraining particle physics models with gravitational waves from the early universe

Abstract

The standard model (SM) of particle physics faces several challenges today, including the existence of neutrino masses, the microscopic description of dark matter, non-zero baryon asymmetry, etc. The tests for most beyond SM (BSM) theories are limited by the accessible collider energy, which will increase to about ! 100 TeV in future colliders like FCC and ILC. To access physics at higher energies, we must look for alternatives to colliders. After the first detection of gravitational waves (GWs) by LIGO in 2015, GW astronomy has emerged as a promising alternative. In this thesis, we study the methods to constrain particle physics models using the stochastic GW imprints from cosmological phase transitions (PTs). Beginning with the theory and background, we describe how the GW background from first-order PTs (FOPTs) and topological defects such as domain walls (DWs) can constrain the model parameter space at upcoming GW observatories.