Probing Cosmic-Ray-Boosted and Supernova-Sourced Sub-GeV Dark Matter with Paleo-Detectors

TL;DR

Paleo-detectors can detect sub-GeV dark matter accelerated by cosmic rays or supernovae over geological timescales, offering sensitivity beyond current experiments and the ability to record Galactic supernova fluxes.

Contribution

This work introduces the use of paleo-detectors for detecting semi-relativistic dark matter from cosmic rays and supernovae, with detailed sensitivity projections.

Findings

Paleo-detectors can probe dark matter-nucleon cross sections for masses from a few MeV to hundreds of MeV.

They can explore parameter regions not accessible to current or near-future experiments.

Paleo-detectors can record dark matter fluxes from Galactic supernovae over geological timescales.

Abstract

Astrophysical dark matter particles with masses well below GeV-scale can be difficult to detect using conventional nuclear recoil experiments due to their low velocities in our Milky Way halo. Elastic scattering with high-energy cosmic rays or thermal production inside core-collapse supernovae can accelerate sub-GeV DM to (semi-)relativistic velocities, producing nuclear recoil energies above the keV threshold that paleo-detectors can record over geological timescales. Using olivine as the target with 100$\,$g$\cdot$Gyr exposure, we compute track length distributions from such (semi-)relativistic dark matter fluxes, incorporating all major backgrounds (neutrinos, uranium-chain neutrons, thorium recoils) with a statistical analysis on an Asimov dataset. We derive 95 C.L. projected sensitivity of paleo-detectors to the DM-nucleon cross section for dark matter masses between a few MeV and hundreds of MeV. Our results show that paleo-detectors are able to probe large parameter regions that are not covered by current and near-future experiments designed to detect dark matter and neutrinos. In particular, paleo-detectors offer a unique ability to record the dark matter flux from Galactic supernova events over geological times. Such cumulative exposure enables sensitivity gains of a few orders of magnitude compared to conventional experiments.