Gravitational waves from dark first order phase transitions and dark photons

Understand

Cold Dark Matter particles may interact with ordinary particles through a dark photon, which acquires a mass thanks to a spontaneous symmetry breaking mechanism.

• We discuss a dark photon model in which the scalar singlet associated to the spontaneous symmetry breaking has an effective potential that induces a first order phase transition in the early Universe.
• Such a scenario provides a rich phenomenology for electron-positron colliders and gravitational waves interferometers, and may be tested in several different channels.
• The hidden first order phase transition implies the emission of gravitational waves signals, which may constrain the dark photon's space of parameters.