Abstract
Collisionless, cold dark matter in the form of weakly interacting massive particles (WIMPs) is well motivated in particle physics, naturally yields the observed relic density, and successfully explains structure formation on large scales. On small scales, however, it predicts too much power, leading to cuspy halos, dense cores, and large numbers of subhalos, in apparent conflict with observations. We consider super-WIMP dark matter, produced with large velocity in late decays at times 10(5) - 10(8) s. As analyzed by Kaplinghat in a more general setting, we find that super-WIMPs have sufficiently large free-streaming lengths and low phase space densities to help resolve small scale structure problems while preserving all of the above-mentioned WIMP virtues.
Highlights
As analyzed by Kaplinghat in a more general setting, we find that super-weakly interacting massive particles (WIMPs) have sufficiently large freestreaming lengths and low phase space densities to help resolve small scale structure problems while preserving all of the above-mentioned WIMP virtues
A common feature of these new hypotheses is that they preserve the successes of standard CDM on large scales, but reduce power on small scales
Note that for uX 1 and X 106 s, natural values in the cases of gravitino and Kaluza-Klein graviton super-WIMPs, the phase space density is in the preferred range to eliminate cuspy halos
Summary
Title Superweakly interacting massive particle solutions to small scale structure problems.
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