Complex angular momentum approach to black hole scattering.

Authors: Andersson, N.-G., Thylwe, K.-E.
Document Type: Article
Pubstate: Published
Journal: Class. Quantum Grav.
Volume: 11   2991-3001
Year: 1994


A description of scalar waves scattered off a Schwarzschild black hole is discussed in terms of complex angular momenta. In the new picture the scattering amplitude is split into a supposedly smooth background integral and a sum over the so-called Regge poles. It is proved that all the relevant Regge poles (the singularities of the S-matrix) must be situated in the first quadrant of the complex lambda (=l+ 1/2 )-plane. We also show that the S-matrix possesses a global symmetry relation S(- lambda )=e/sup -2i pi lambda / S( lambda ), which makes it possible to simplify considerably the background integral. Finally, a formal basis for actual computations of Regge poles and the associated residues is outlined.