HEP Theory Journal Club

Bubble wall velocity and gravitational waves from first-order QCD phase transition

Benoit Laurent

McGill University

Although the QCD phase transition is a crossover in the standard model, nonstandard effects such as a large lepton asymmetry are known to make it first order, with possible applications to gravitational wave production. This process is sensitive to the speed of the bubble walls during the phase transition, which is difficult to compute from first principles. In this talk, I will take advantage of recent progress on wall speed determinations to provide a simple estimate which constrains the wall speed to be significantly lower than what has been used in previous literature. This, in turn, strongly suppresses the production of gravitational waves, to a level that is just out of reach of the most sensitive projected experiment for this signal.