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

Journal Article · 11 August 2024 · Physical Review. D.

DOI: https://doi.org/10.1103/PhysRevD.110.L031702 · OSTI ID:2429010

Bhattiprolu, Prudhvi N. ; McGehee, Robert ; Pierce, Aaron

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 $\psi$ which interacts solely with DM $\chi$ via the exchange of a heavy scalar $\mathrm{\Phi }$ . We illustrate the impact of a dark sink by adding one to a DM freeze-in model in which $\chi$ couples to a light dark photon ${\gamma }^{\prime }$ 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 $\psi$ ’s to dark radiation; consistency with existing data limits the maximum attainable cross section. For DM with a mass between $\mathrm{MeV}-\mathcal{O}\left(10\mathrm{GeV}\right)$ , 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

• Sponsoring Organization: USDOE
• Grant/Contract Number: SC0007859
• OSTI ID: 2429010
• Alternate ID(s): OSTI ID: 2565575
• Journal Information: Physical Review. D., Journal Name: Physical Review. D. Journal Issue: 3 Vol. 110; ISSN PRVDAQ; ISSN 2470-0010
• Publisher: American Physical SocietyCopyright Statement
• Country of Publication: United States
• Language: English