Scattering Searches for Dark Matter in Subhalos: Neutron Stars, Cosmic Rays, and Old Rocks.

Area of Science:

• Cosmology and astrophysics
• Particle physics
• Astroparticle physics

Background:

• Dark matter is hypothesized to cluster on subkiloparsec scales, forming compact subhalos.
• The majority of Galactic dark matter might be concentrated within these subhalos.
• Decades of null results from direct dark matter detection experiments may stem from rare Earth-subhalo encounters.

Purpose of the Study:

• To investigate novel methods for detecting dark matter within subhalos.
• To explore interactions between subhalo dark matter and standard model particles.
• To establish new observational and geological strategies for dark matter subhalo identification.

Main Methods:

• Analyzing kinetic energy transfer from subhalo collisions with neutron stars, leading to observable brightening.
• Investigating the detectable effects of subhalo dark matter scattering with cosmic rays.
• Searching for dark matter tracks in Paleolithic minerals from historic Earth-subhalo encounters.

Main Results:

• New detection strategies proposed, including single-star measurements and Galactic disk surveys.
• First bounds on self-interacting dark matter in subhalos derived from the pulsar PSR J2144-3933.
• Identification of potential observational signatures for subhalo dark matter across multiple interaction pathways.

Conclusions:

• Subhalo dark matter searches offer a promising avenue for discovery, complementing traditional direct detection methods.
• These methods could reveal dark matter subhalos with masses ranging from gigatons to solar masses.
• The proposed searches span vast ranges of dark matter cross sections and masses, significantly broadening the scope of dark matter exploration.