ABSORPTION OF ANGULAR-MOMENTUM BY BLACK-HOLES AND D-BRANES

We consider the absorption of higher angular momentum modes of scalars into black holes, at low energies, and ask if the resulting cross sec tions are reproduced by a D-brane model. To get the correct dependence on the volume of the compactified dimensions, we must let the absorbi ng element in the brane model have a tension that is the geometric mea n of the tensions of the D-string and an effective stringlike tension obtained from the D5-brane; this choice is also motivated by T-duality . In a dual model we note that the correct dependence on the volume of the compact dimensions and the coupling arise if the absorbing string is allowed to split into many strings in the process of absorbing a h igher angular momentum wave. We obtain the required energy dependence of the cross section by carrying out the integrals resulting from part itioning the energy of the incoming quantum into vibrations of the str ing. (C) 1998 Elsevier Science B.V.