General N=1 supersymmetric fluxes in massive type IIA string theory

We study conditions on general fluxes of massive type IIA supergravity that lead to four-dimensional backgrounds with M = 1 supersymmetry. We derive these conditions in the case of SU(3)- as well as SU(2)-structures. SU(3) -structures imply that the internal space is constrained to be a nearly Kahler manifold with all the turned on fluxes, and the negative cosmological constant proportional to the mass parameter, and the dilaton fixed by the quantized ratio of the three-form and four-form fluxes. We further discuss the implications of such flux vacua with added intersecting D6-branes, leading to the chiral non-Abelian gauge sectors (without orientifold projections). Examples that break SU (3) -structures to SU(2)-ones allow for the internal space conformally flat (up to orbifold and orientifold projections), for which we give an explicit example. These results provide a starting point for further study of the four-dimensional (chiral) M = 1 supersymmetric solutions of massive type IIA supergravity with D-branes and fluxes, compactified on orientifolds. (C) 2004 Elsevier B.V. All rights reserved.