We discuss a generalized form of IIA/IIB supergravity depending on all R-R potentials C~(p) (p = 0, 1,… 9) as the effective field theory of Type IIA/IIB superstring theory. For the IIA case we explicitly break this R-R democracy to either p ≤ 3 or p ≥ 5 which allows us to write a new bulk action that can be coupled to N = 1 supersymmetric brane actions. The case of 8-branes is studied in detail using the new bulk & brane action. The supersymmetric negative tension branes without matter excitations can be viewed as orientifolds in the effective action. These D8-branes and O8-planes are fundamental in Type I' string theory. A BPS 8-brane solution is given which satisfies the jump conditions on the wall. As an application of our results we derive a quantization of the mass parameter and the cosmological constant in string units.
展开▼
