String theory and classical absorption by threebranes
Abstract
Lowenergy absorption cross sections for various particles falling into extreme nondilatonic branes are calculated using string theory and worldvolume field theory methods. The results are compared with classical absorption by the corresponding gravitational backgrounds. For the selfdual threebrane, earlier work by one of us demonstrated precise agreement of the absorption cross sections for the dilaton, and here we extend the result to RamondRamond scalars and to gravitons polarized parallel to the brane. In string theory, the only absorption channel available to dilatons and RamondRamond scalars at leading order is conversion into a pair of gauge bosons on the threebrane. For gravitons polarized parallel to the brane, scalars, fermions and gauge bosons all make leadingorder contributions to the cross section, which remarkably add up to the value predicted by classical gravity. For the twobrane and fivebrane of Mtheory, numerical coefficients fail to agree, signaling our lack of a precise understanding of the worldvolume theory for large numbers of coincident branes. In many cases, we note a remarkable isotropy in the final state particle flux within the brane. We also consider the generalization to higher partial waves of minimally coupled scalars. We demonstrate agreement for the threebrane at l = 1 and indicate that further work is necessary to understand l > 1.
 Publication:

Nuclear Physics B
 Pub Date:
 February 1997
 DOI:
 10.1016/S05503213(97)003258
 arXiv:
 arXiv:hepth/9703040
 Bibcode:
 1997NuPhB.499..217G
 Keywords:

 High Energy Physics  Theory
 EPrint:
 27 pages, harvmac