Hairy magnetic and dyonic black holes in the Standard Model

Spherically symmetric magnetic and dyonic black holes with a magnetic charge Q = 2 are studied in the Standard Model and general relativity. A magnetically charged black hole with mass below 9.3 × 1035 GeV has a “hairy” cloud of electroweak gauge and Higgs fields outside the event horizon with 1/mW in size. An extremal magnetic black hole has a hair mass of 3.6 TeV, while an extremal dyonic black hole has an additional mass of q2 × 1.6 GeV for a small electric charge q ≪ 2π/e2. A hairy dyonic black hole with an integer charge is not stable and can decay into a magnetic one plus charged fermions. On the other hand, a hairy magnetic black hole can evolve via Hawking radiation into a nearly extremal one that is cosmologically stable and an interesting object to be searched for.