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In a recent publication we studied the decay rate of primordial black holes perceiving the dark dimension, an innovative five-dimensional (5D) scenario that has a compact space with characteristic length scale in the micron range. We demonstrated that the rate of Hawking radiation of 5D black holes slows down compared to 4D black holes of the same mass. Armed with our findings we showed that for a species scale of , an all-dark-matter interpretation in terms of primordial black holes should be feasible for black hole masses in the range . As a natural outgrowth of our recent study, herein we calculate the Hawking evaporation of near-extremal 5D black holes. Using generic entropy arguments we demonstrate that Hawking evaporation of higher-dimensional near-extremal black holes proceeds at a slower rate than the corresponding Schwarzschild black holes of the same mass. Assisted by this result we show that if there were 5D primordial near-extremal black holes in nature, then a primordial black hole all-dark-matter interpretation would be possible in the mass range , where is a parameter that controls the difference between mass and charge of the associated near-extremal black hole. Published by the American Physical Society2024
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Monochromatic mass spectrum of primordial black holes
During slow-roll inflation, nonperturbative transitions can produce bubbles of metastable vacuum. These bubbles expand exponentially during inflation to superhorizon size, and later collapse into black holes when the expansion of the Universe is decelerating. Estimating the rate for these transitions during a time-dependent slow-roll phase requires the development of new techniques. Our results show that in a broad class of models, the inflationary fine-tuning that gives rise to small density fluctuations causes these bubbles to appear only during a time interval that is short compared to the inflationary Hubble time. As a result, despite the fact that the final mass of the black hole is exponentially sensitive to the moment bubbles form during inflation, the resulting primordial black hole mass spectrum can be nearly monochromatic. If the transition occurs near the middle of inflation, the mass can fall in the “asteroid” range in which all known observations are compatible with black holes comprising 100% of dark matter.
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- PAR ID:
- 10655208
- Publisher / Repository:
- American Physical Society
- Date Published:
- Journal Name:
- Physical review D
- Volume:
- 111
- Issue:
- 2
- ISSN:
- 2470-0029
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1103/PhysRevD.111.023538
