New Formulations of D=10 Supersymmetry and D8-O8 Domain Walls

TL;DR

This work develops three consistent formulations of D=10 Type II supergravity that accommodate all RR potentials and support explicit D8--O8 domain-wall constructions. By breaking RR democracy in IIA and introducing a dual action with a dynamical mass parameter $G^{(0)}$ (via a 9-form), the authors build a supersymmetric bulk+brane system that includes orientifold planes and D8-branes, yielding a BPS 8-brane solution with Killing spinors and a quantized mass parameter $m$ in string units. The analysis reveals a maximal permissible distance between the walls and derives the associated flow equations for supersymmetric domain walls, linking the results to Type ${ m I'}$ string theory and RS-like brane-world scenarios. Together, these results provide a concrete, string-theoretic framework for D=10 domain walls with controlled supersymmetry and a suite of exact solutions and consistency checks that can guide broader explorations of higher-dimensional brane worlds.

Abstract

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. It implies a quantization of the mass parameter in string units. Also we find a maximal distance between the two walls, depending on the string coupling and the mass parameter. We derive the same results via supersymmetric flow equations.