Particle emission rates from a black hole: Massless particles from an uncharged, nonrotating hole

Hawking has predicted that a black hole will emit particles as if it had a temperature proportional to its surface gravity. This paper combines Hawking's quantum formalism with the black-hole perturbation methods of Teukolsky and Press to calculate the emission rate for the known massless particles. Numerical results indicate that a hole of mass M≫10¹⁷ g should emit a total power output of 2×10^-4ℏc⁶G^-2M^-2, of which 81% is in neutrinos, 17% is in photons, and 2% is in gravitons. These rates plus an estimate for the emission rates of massive particles from smaller holes allow one to infer that a primordial black hole will have decayed away within the present age of the universe if and only if its initial mass was M<(5±1)×10¹⁴ g.