Here’s an interesting chain of thought…
Imagine a black hole sucking in protons and electrons. With their higher mass, protons are likely to be preferentially sucked, giving the black hole a positive charge. (That’s not so unusual in space: a similar mechanism can give planets a charge because electrons escape their gravity more easily.)
But black holes also create such strong electrostatic fields at the horizon that positrons and electrons simply appear out of the vacuum.
In those circumstances, it’ll look as if the protons being sucked into the black hole are being converted into positrons.
So these kinds of black holes will look and behave like antimatter factories, say Cosimo Bambi from Wayne State University in Detroit and pals.
How might we we spot these exotic objects? Bambi and friends say a sure signature would be an excess of positrons in cosmic rays with an energy between 1 and 100 MeV coming from a black hole.
Anybody seen any of these?
Ref: arxiv.org/abs/0806.3440: Black Holes as Antimatter Factories