More on black holes perceiving the dark dimension

In the last two years, the dark dimension scenario has emerged as focal point of many research interests. In particular, it functions as a stepping stone to address the cosmological hierarchy problem and provides a colosseum for dark matter contenders. We reexamine the possibility that primordial black holes (PBHs) perceiving the dark dimension could constitute all of the dark matter in the Universe. We reassess limits on the abundance of PBHs as dark matter candidates from γ-ray emission resulting from Hawking evaporation. We reevaluate constraints from the diffuse γ-ray emission in the direction of the Galactic Center that offer the best and most solid upper limits on the dark matter fraction composed of PBHs. The revised mass range that allows PBHs to assemble all cosmological dark matter is estimated to be 1015≲MBH/g≲1021. We demonstrate that, due to the constraints from γ-ray emission, quantum corrections due to the speculative memory burden effect do not modify this mass range. We also investigate the main characteristics of PBHs that are localized in the bulk. We show that PBHs localized in the bulk can make all cosmological dark matter if 1011≲MBH/g≲1021. Finally, we comment on the black holes that could be produced if one advocates a space with two boundaries for the dark dimension. Published by the American Physical Society 2024