Probing Asymmetric Dark Matter with Gravitational Waves

Models of asymmetric dark matter offer a simultaneous solution to two of the most intriguing open questions in particle physics: What is the nature of dark matter? What is the origin of the matter-antimatter asymmetry of the Universe? In this presentation, I will show how this class of models can be probed in gravitational wave experiments. I will concentrate on a theory with the Standard Model symmetry extended by an additional SU(2) group, under which the leptons and new fermionic partners form doublets. Interestingly, one of the new fermions satisfies the requirements for being the dark matter particle. The scale of breaking of this extra SU(2) symmetry is high and the model allows for a successful high-scale baryogenesis, i.e., explaining today's domination of matter over antimatter. This is achieved via a strong first order phase transition in the early Universe, which, in turn, results in the production of gravitational waves. The model predicts also the formation of topological defects like domain walls, also leading to the emission of gravitational radiation through their annihilation. As I will demonstrate, the expected gravitational wave spectrum of the model is within the reach of upcoming gravitational wave detectors, including DECIGO, Big Bang Observer, Cosmic Explorer and Einstein Telescope. This presents an entirely novel way of probing this type of theories, otherwise completely inaccessible in conventional particle physics experiments.