MACHOs are dead, WIMPs are a no-show — say hello to SIMPs
The nature of dark matter remains elusive, with numerous experimental searches for WIMPs coming up empty-handed and MACHOs all but abandoned. Theorists have proposed a different type of dark matter particle, a strongly interacting massive particle or SIMP, that differs from WIMPs in that they interact strongly with one another and hardly at all with normal matter. The dark matter structure of a galaxy pile-up could be evidence for SIMPs. …read more
