S duality and dyonic p-brane solutions in type II string theory.

We show how a solitonic “magnetically” charged p-brane solution of a given supergravity theory, with the magnetic charge carried by an antisymmetric tensor gauge field, can be generalized to a dyonic solution. We discuss the cases of ten-dimensional and elevendimensional supergravity in more detail and a new dyonic five-brane solution in ten dimensions is given. Unlike the purely electrically or magnetically charged five-brane solution the dyonic five-brane contains non-zero Ramond–Ramond fields and is therefore an intrinsically type II solution. The solution preserves half of the type II spacetime supersymmetries. It is obtained by applying a solution-generating SL(2,R) × SL(2,R) S duality transformation to the purely magnetically charged five-brane solution. One of the SL(2,R) duality transformations is basically an extension to the type II case of the six-dimensional Z2 string/string duality. We also present an action underlying the type IIB supergravity theory. E-mail: [email protected] E-mail: [email protected] E-mail: [email protected] Address after October 1st: CERN Theory Division, CH-1211, Genève 23, Switzerland.