SIMP v WIMP: Novel thermal relic mechanism for dark matter creation in the early universe

(Phys.org)--Our current understanding of the universe is that the majority of its mass consists of dark matter (DM) - but there's a wrinkle: Despite having an idea about some of its properties - dark matter is cold, massive, has neither color nor electrical charge, and does not self-interact very strongly, so that it is detected through its gravitational interactions with ordinary matter and radiation - scientists don't know what dark matter actually is. That said, and as might well be expected,...