Comment on "keV Neutrino Dark Matter in a Fast Expanding Universe" by Biswas et al [CL]

http://arxiv.org/abs/1810.06795


Biswas et al. found that the thermal relic density of a dark matter particle freezing out while the universe’s energy density is dominated by a non-standard extra component $\phi$, whose energy density redshifts faster than radiation, can be greatly suppressed. Here we show that this result, which contradicts extensive previous literature, is incorrect: the mistake lies with the assumption that the (decoupled) extra component $\phi$ contributes to the entropic degrees of freedom relevant for dark matter freeze out. If this were the case, a completely different approach would be needed to calculate the dark matter relic abundance, with dramatically different results.

Read this paper on arXiv…

N. Fernandez and S. Profumo
Wed, 17 Oct 18
74/96

Comments: N/A