Speaker
Description
QCD-like dark sectors may undergo a first-order chiral phase transition in the early Universe that may lead to production of stochastic gravitational wave background. We consider a class of such dark sectors that feature also dark pions as viable dark matter candidates and study the corresponding strength of the gravitational-wave signal. Importantly, the chiral phase transition is of first order only if the pion mass is much smaller than the critical temperature. One way how to achieve correct dark matter abundance for small pion masses is to consider a secluded dark sector. We show that for such scenario, the gravitational wave signal is, unfortunately, strongly suppressed. Alternative scenarios with possibly stronger gravitational wave signal are also discussed.
