Dark sink enhances the direct detection of freeze-in dark matter

We describe a simple dark sector structure which, if present, has implications for the direct detection of dark matter (DM);. A dark sink transports energy density from the DM into light dark-sector states that do not appreciably contribute to the DM density. As an example, we consider a light, neutral fermion ψ which interacts solely with DM χ via the exchange of a heavy scalar Φ. We illustrate the impact of a dark sink by adding one to a DM freeze-in model in which χ couples to a light dark photon γ ′ which kinetically mixes with the Standard Model (SM) photon. This freeze-in model (absent the sink) is itself a benchmark for ongoing experiments. In some cases, the literature for this benchmark has contained errors; we correct the predictions and provide them as a public code. We then analyze how the dark sink modifies this benchmark, solving coupled Boltzmann equations for the dark-sector energy density and DM yield. We check the contribution of the dark sink ψ ’s to dark radiation; consistency with existing data limits the maximum attainable cross section. For DM with a mass between MeV − O ( 10 GeV ), adding the dark sink can increase predictions for the direct detection cross section all the way up to the current limits. Published by the American Physical Society 2024

Authors

Prudhvi N. Bhattiprolu; Robert McGehee; Aaron Pierce

Published

Aug 12, 2024

Journal or venue

Physical Review D

DOI

10.1103/physrevd.110.l031702

Paper type

journal article

Source

Crossref