Primordial gravitational waves from dark strongly-coupled Yang-Mills sectors

Sammanfattning

We perform a comprehensive cosmological analysis of stable scalar glueballs arising in pure SU(N) Yang-Mills theories focusing on N=3,4,5 which serve as natural candidates for models of self-interacting dark matter. The key characteristic of these theories is that they exhibit strong first-order confinement-deconfinement phase transitions which would give rise to a stochastic gravitational wave background. In our investigation we employ an effective thermal theory which relies on results from lattice simulations. We begin by reproducing some key results concerning glueball dark matter including the relic abundance and the equation of state. Thereafter, we perform a detailed analysis of the phase transition and calculation of the thermal parameters. Finally, we conclude the analysis by making a novel prediction for the gravitational wave spectra associated with the first-order phase transitions. With regards to the relic abundance, we find excellent agreement with the previous works utilizing the same approach showing again that glueballs could account for the totality of dark matter. Due to constraints on the temperature of the dark sector, we find that detectable gravitational wave signals can not be produced in the cases where glueballs account for the totality of dark matter.