  We show that black holes with a Schwarzschild radius of the order of the
electroweak scale may act as seeds for the baryon number violation within the
Standard model via sphaleron transitions. The corresponding rate is faster than
the one in the pure vacuum and baryon number violation around black holes can
take place during the evolution of the universe after the electroweak phase
transition. We show however that this does not pose any threat for a
pre-existing baryon asymmetry in the universe.

Cosmology and Nongalactic Astrophysics;General Relativity and Quantum Cosmology;High Energy Physics - Phenomenology;High Energy Physics - Theory