## Long-distance interactions of D-brane bound states and longitudinal five-brane in M(atrix) theory

We discuss long-distance, low-velocity interaction potentials for processes involving a longitudinal M5-brane (corresponding in type IIA theory language to the 1/4 supersymmetric bound state of a 4-brane and 0-brane). We consider the following scattering configurations: (a) a D=11 graviton off longitudinal M5-brane, or, equivalently, 0-branes off marginal 4{parallel}0 bound state; an (b) M2-brane off longitudinal M5-brane, or, equivalently, a nonmarginal 2+0 bound state off marginal 4{parallel}0 bound state; (c) two parallel longitudinal M5-branes, or, equivalently, two 4{parallel}0 marginal bound states. We demonstrate the equivalence between the classical string theory (supergravity) and M(atrix) model (one-loop super Yang-Mills) results for the leadingmore »