Strongly interacting massive particle
Template:Short description A strongly interacting massive particle (SIMP) is a hypothetical particle that interacts strongly between themselves and weakly with ordinary matter, but could form the inferred dark matter despite this.<ref name="wand"> Template:Cite book</ref><ref> Template:Cite journal</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Strongly interacting massive particles have been proposed as a solution for the ultra-high-energy cosmic-ray problem<ref name="chung"> Template:Cite journal</ref><ref name="albq"> Template:Cite journal</ref> and the absence of cooling flows in galactic clusters.<ref name="qin"> Template:Cite journal</ref><ref name="chuz"> Template:Cite journal</ref>
Various experiments and observations have set constraints on SIMP dark matter from 1990 onward.<ref name="stark"> Template:Cite journal</ref><ref name="cyb"> Template:Cite journal.</ref><ref name="zahar"> Template:Cite journal</ref><ref name="wdn"> Template:Cite journal</ref><ref name="mcgr"> Template:Cite book</ref><ref name="javor"> Template:Cite journal</ref>
SIMP annihilations would produce significant heat. DAMA set limits with NaI(Tl) crystals.<ref name="wdn"/>Template:Citation needed
Measurements of Uranus's heat excess exclude SIMPs from 150 MeV to 104 GeV.<ref name="mitr"> Template:Cite journal</ref> Earth's heat flow significantly constrains any cross section.<ref> Template:Cite journal</ref>