The Dark Universe: Primordial Black Hole $\leftrightharpoons$ Dark Graviton Gas Connection [CL]

http://arxiv.org/abs/2210.02475


We study the possible correspondence between 5-dimensional primordial black holes and massive 5-dimensional KK gravitons as dark matter candidate within the recently proposed dark dimension scenario that addresses the cosmological hierarchy problem. First, we show that in the local universe a population of 5-dimensional black holes with $M_{\rm BH}\sim 7\times 10^{13}~{\rm g}$ would be practically indistinguishable from a KK tower of dark gravitons with $m_{\rm DM} \sim 50~{\rm keV}$. Second, we connect the mass increase of 5-dimensional black holes and the related temperature decrease with the cooling of the tower of massive spin-2 KK excitations of the graviton. The dark gravitons are produced at a mass $\sim 1 – 50~{\rm GeV}$ and the bulk of their mass shifts down to roughly $1 – 100~{\rm keV}$ today. The cooling of the system proceeds via decay to lighter gravitons without losing much total mass density, resembling the intra-tower decays that characterize the cosmological evolution of the dynamical dark matter framework. We associate the intra-tower decays of the graviton gas with the black hole growth through accretion. We also discuss that the primordial black hole $\leftrightharpoons$ dark graviton gas connection can be nicely explained by the bound state picture of black holes in terms of gravitons.

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L. Anchordoqui, I. Antoniadis and D. Lust
Fri, 7 Oct 22
15/62

Comments: 4 pages, 2 figures. arXiv admin note: text overlap with arXiv:2206.07071