Strongly interacting massive particle

Strongly interacting massive particles (SIMPs) are hypothetical particles that interact strongly with ordinary matter, but could form the inferred dark matter despite this.

Strongly interacting massive particles have been proposed as a solution for the ultra-high-energy cosmic-ray problem and the absence of cooling flows in galactic clusters.

Various experiments and observations have set constraints on SIMP dark matter from 1990 onward.

SIMPs annhilations would produce significant heat. DAMA set limits with NaI(Tl) crystals.

Measurements of Uranus's heat excess exclude SIMPS from 150 MeV to 10⁴ GeV. Earth's heat flow significantly constrains any cross section.