Mr Alexander Gussmann (Arnold-Sommerfeld-Center, LMU Munich)
Standard folk-theorem arguments claim that global charges, such as baryon number, cannot be conserved by semiclassical black holes. We argue that the existence of black holes with classical skyrmion hair invalidates these standard arguments. By carefully analyzing the standard arguments based on a Gedankenexperiment in which a black hole is seemingly-unable to return the baryon number that it swallowed, we identify inconsistencies in this reasoning, which does not take into the account neither the existence of skyrmion black holes nor the baryon/skyrmion correspondence. Using a refined Gedankenexperiment, we argue that one should rethink the option of baryon number conservation by semiclassical black holes and provide arguments in favor of baryon number conservation. If a black hole cannot destroy baryon number, this can have important phenomenological consequences.