Greybody factors in black-hole physics modify the naive Planckian spectrum that is predicted for Hawking radiation when working in the limit of geometrical optics. We consider the Schwarzschild geometry in $(3+1)$ dimensions, and analyze the Regge-Wheeler equation for arbitrary particle spin $s$ and wave-mode angular momentum $\ell$, deriving rigorous bounds on the greybody factors as a function of $s$, $\ell$, wave frequency $\omega$, and the black-hole mass $m$.

• Received 23 June 2008

DOI:https://doi.org/10.1103/PhysRevD.78.101502