Testing Gauged Baryon and Lepton Number Models with Gravitational Waves

I will show that new types of gravitational wave signatures are expected in extensions of the Standard Model with two U(1) gauge symmetries broken at high energy scales. In particular, I will focus on the case with gauged U(1) baryon number and U(1) lepton number. Such models accommodate dark matter, explain the matter-antimatter asymmetry of the Universe through leptogenesis, and give rise to the seesaw mechanism for neutrinos. The gravitational wave signals consist of contributions from first order phase transitions, cosmic strings and domain walls. The new signatures are within the reach of future detectors, such as Cosmic Explorer, Einstein Telescope, DECIGO, Big Bang Observer, and LISA.