Black hole dynamics from instanton strings

A D-5-brane bound state with a self-dual field strength on a 4-torus isconsidered. In a particular case this model reproduces the D5-D1 brane boundstate usually used in the string theory description of 5-dimensional blackholes. In the limit where the brane dynamics decouples from the bulk the Higgsand Coulomb branches of the theory on the brane decouple. Contrasting with theusual instanton moduli space approximation to the problem the Higgs branchdescribes fundamental excitations of the gauge field on the brane. Uponreduction to 2-dimensions it is associated with the so-called instantonstrings. Using the Born-Infeld action for the D-5-brane we determine thecoupling of these strings to a minimally coupled scalar in the black holebackground. The supergravity calculation of the cross section is found to agreewith the D-brane absorption probability rate calculation. We consider the nearhorizon geometry of our black hole and elaborate on the corresponding dualitywith the Higgs branch of the gauge theory in the large N limit. A heuristicargument for the scaling of the effective string tension is given.Comment: 37 pages, latex. Typos corrected, SUSY field configuration argued to be valid even when DBI corrections are important and two references adde