http://arxiv.org/abs/2203.14424
We show that the stochastic Gravitational Waves (GW) signal generated during the (p)reheating era can act as a novel probe of the non-thermal dark matter production in the early Universe. Such scenarios are of utmost interest when no other interaction between the visible and dark sectors is present, therefore having no other detectability prospects. We consider the remnant energy in the coherently oscillating inflaton zeroth mode to contribute as the observed relic dark matter density in the Universe. To fully capture the nonlinear dynamics and the effects of back-reactions during the oscillation, we resort to fully nonlinear lattice simulation with pseudo-spectral methods to eliminate the differencing noises. We investigate for models whose behavior during the reheating era is of quadratic ($m_{\Phi}^2\Phi^2$ type) and find the typical primordial stochastic GW background (SGWB) spectrum from scatterings among highly populated inflaton modes behaving like matter, as expected, during this nonlinear phase. We predict the detectable dark matter mass ranges within the future GW detectors such as BBO, DECIGO, PTA, AION-MAGIS, and CE to be (MeV – TeV) ranges. We conclude that with the current and future GW detectors operating at high frequencies one will be able to probe non-thermal dark matter which is otherwise impossible to test at laboratories and astrophysical searches due to feeble or no interaction among the visible and dark sectors.
A. Ghoshal and P. Saha
Tue, 29 Mar 22
38/73
Comments: 10 pages, 2 figures