N=4 supergravity for Type IIB on T^6/Z_2 in presence of fluxes

We report on the construction of four dimensional gauged supergravity models that can be interpreted as type IIB orientifold compactification in presence of 3-form fluxes and D3--branes. We mainly address our attention to the symplectic embedding of the U-duality group of the theory and the consequent choice of the gauge group, whose four dimensional killing vectors are the remnant of the ten dimensional fluxes. We briefly discuss the structure of the scalar potential arising from the gauging and the properties of the killing vectors in order to preserve some amount of supersymmetry.Comment: LaTeX, iopart class, 9 pages, Contribution to the proceedings of the workshop of the RTN Network "The quantum structure of space-time and the geometric nature of fundamental interactions",Copenhagen, September 2003 2nd version, references adde

Dual versions of extended supergravities

Recently, using the model of N=2 supergravity -- vector multiplets interaction with the scalar field geometry $SU(1,m)/SU(m)\otimes U(1)$ as an example, we have shown that even when the scalar field geometry is fixed, one can have a whole family of the Lagrangians, which differ by vector field duality transformation. In this paper we carry out the construction of such families for the case of N=3 and N=4 supergravities, the scalar field geometry being $SU(3,m)/SU(3)\otimes SU(m)\otimes U(1)$ and $SU(1,1)/U(1)\otimes O(6,m)/O(6)\otimes O(m)$, correspondingly. Moreover, it turns out that these families contain, as a partial case, the models describing the interaction of arbitrary number of vector multiplets with our hidden sectors, admitting spontaneous supersymmetry breaking without a cosmological term.Comment: 9 pages, plain LaTeX, no figure

N=6 gauged supergravities from generalized dimensional reduction

We construct new N=6 gauged supergravities in four and five dimensions using generalized dimensional reduction. Supersymmetry is spontaneously broken to N=4,2,0 with vanishing cosmological constant. We discuss the gaugings of the broken phases, the scalar geometries and the spectrum. Generalized orbifold reduction is also considered and an N=3 no-scale model is obtained with three independent mass parameters.Comment: 1+9 pages, accepted for publication in Physics Letters

N=4 gauged supergravity and a IIB orientifold with fluxes

We analyze the properties of a spontaneously broken D=4, N=4 supergravity without cosmological constant, obtained by gauging translational isometries of its classical scalar manifold. This theory offers a suitable low energy description of the super-Higgs phases of certain Type-IIB orientifold compactifications with 3-form fluxes turned on. We study its N=3,2,1,0 phases and their classical moduli spaces and we show that this theory is an example of no-scale extended supergravity.Comment: Misprints corrected. Version appeared on NJP 4 (2002)7

Axion gauge symmetries and generalized Chern-Simons terms in N=1 supersymmetric theories

We compute the form of the Lagrangian of N=1 supersymmetric theories with gauged axion symmetries. It turns out that there appear generalized Chern-Simons terms that were not considered in previous superspace formulations of general N=1 theories. Such gaugings appear in supergravities arising from flux compactifications of superstrings, as well as from Scherk-Schwarz generalized dimensional reduction in M-theory. We also present the dual superspace formulation where axion chiral multiplets are dualized into linear multiplets.Comment: References added and few misprints correcte