Gravitational waves from a very strong electroweak phase transition

Understand

We investigate the production of a stochastic background of gravitational waves in the electroweak phase transition.

• We consider extensions of the Standard Model which can give very strongly first-order phase transitions, such that the transition fronts either propagate as detonations or run away.
• To compute the bubble wall velocity, we estimate the friction with the plasma and take into account the hydrodynamics.
• We track the development of the phase transition up to the percolation time, and we calculate the gravitational wave spectrum generated by bubble collisions, magnetohydrodynamic turbulence, and sound waves.