Gravitational Waves From a Dark (Twin) Phase Transition

Understand

In this work, we show that a large class of models with a composite dark sector undergo a strong first order phase transition in the early universe, which could lead to a detectable gravitational wave signal.

• We summarise the basic conditions for a strong first order phase transition for SU(N) dark sectors with n_f flavours, calculate the gravitational wave spectrum and show that, depending on the dark confinement scale, it can be detected at eLISA or in pulsar timing array experiments.
• The gravitational wave signal provides a unique test of the gravitational interactions of a dark sector, and we discuss the complementarity with conventional searches for new dark sectors.
• The discussion includes Twin Higgs and SIMP models as well as symmetric and asymmetric composite dark matter scenarios.