Primordial black holes from collapsing antimatter

Abstract

In this paper a simple (i.e. free of fine-tuning, etc.) new mechanism for primordial black hole formation based on the collapse of large antimatter systems in the early Universe is introduced. A peculiarity of this process is that, compared to their material counterparts, the collapse of large antimatter systems takes much less time due to the reversed thermodynamics of antimatter, an idea which has been proposed in our earlier paper. This model has several testable predictions. The first is that the photon-baryon ratio is roughly computable and is equal to $1.95\times 10^9$ which is quite close to its experimentally confirmed value. The second is that the mass of black holes arising from this mechanism is at least $10^5$-$10^6M_\odot$ hence they contribute to the super- or hypermassive end of the primordial black hole mass spectrum. The third prediction is that these sort of primordial black holes constitute at least $20\%$ of dark matter. Last but not least the observed current asymmetry of matter and antimatter, even if their presence in the Universe was symmetric in the beginning, acquires a natural explanation, too.