Abstract

A gravitational wave background from a first order phase transition at the electroweak scale may be observable with future detectors such as LISA . While the Standard Model does not predict a first order phase transition, these occur in many BSM scenarios, including various dark matter models. Therefore, detecting a stochastic gravitational wave background could point to new physics, while a null detection could constrain or even exclude many BSM models. However, finding a signal in LISA coming from an early universe phase transition is not straightforward, due to the expected instrument noises and astrophysical backgrounds, such as a the one produced by a population of white dwarf binaries. In this talk I will present our recent advances in recovering injected phase transition signals in realistic simulated LISA data, where we exploit the annual modulation of the astrophysical sources to improve the signal separation. I will also discuss how we could map such a gravitational wave signal onto the underlying phase transition parameters by using parameterised templates as an approximation to a more complete physical model, which greatly speeds up the process.