Cosmology

Out with the WIMPs, in with the SIMPs?

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Science  07 Nov 2014:
Vol. 346, Issue 6210, pp. 713-714
DOI: 10.1126/science.346.6210.713-f

Physicists seeking to identify dark matter—the stuff whose gravity may bind the galaxies—may have been stalking the wrong particle. The favorite candidate is the weakly interacting massive particle (WIMP), thought to have a mass between 1 and 1000 times that of a proton and interacting with each other and ordinary matter only through the weak nuclear force. But hypothetical strongly interacting massive particles (SIMPs) would do just as good a job at explaining the stuff, report Hochberg et al. They argue that dark matter could also consist of lighter particles that have a mass around one-10th of the proton and interact with one another very strongly, but with ordinary matter much more weakly than WIMPs. Strongly interacting dark matter would help resolve some differences between dark matter simulations and observed properties of galaxies.

Phys. Rev. Lett. 10.1103/PhysRevLett.113.171301 (2014).

SIMPs would help reconcile observed properties of galaxies and models of dark matter distribution (shown).

CREDIT: RALF KAEHLER, OLIVER HAHN AND TOM ABEL/KAVLI INSTITUTE FOR PARTICLE ASTROPHYSICS AND COSMOLOGY

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