Constraining Dark Matter Candidates in Early Matter Dominated Era Cosmologies

An early matter dominated era (EMDE) before the onset of the radiation dominated era (RDE) is a prediction of many early Universe theories. Subhorizon dark matter (DM) density perturbations grow faster during an EMDE than during an RDE, leading to an increased abundance of microhalos that form far earlier than in standard models of structure formation. This enhancement of small-scale structure boosts the DM annihilation rate, and I calculate the resulting boost factors B(z) using the Peak-to-Halo (P2H) method. I have used predictions of the global 21 cm signal to forecast bounds on the DM annihilation cross section in cosmologies with EMDEs. However, these constraints do not take into consideration whether the allowed DM particle properties also lead to the observed relic abundance. I propose to develop a computational pipeline to simultaneously constrain DM candidates based on their annihilation rate and the resulting relic abundance. In addition, I have found that the P2H method leads to unphysical values of the boost factor for power spectra with shallow small-scale cutoffs. I propose to modify the method to correctly predict B(z) for these power spectra.

Hwan Bae

Dept. of Physics and Astronomy

UNC Chapel Hill

Zoom Link: https://unc.zoom.us/j/95066569411?pwd=TVNQaC9Ya09BRitiUHYvSWMzY0R3QT09

Meeting ID: 950 6656 9411

Passcode: 570328