Recent Developments in Superstring Phenomenology

Recent developments in superstring phenomenology are summarized on a non-technical level. (Talk presented at the XXVIIth Rencontre de Moriond on Electroweak Interactions and Unified Theories.)Comment: 13 page

Supersymmetric AdS_7 backgrounds in half-maximal supergravity and marginal operators of (1,0) SCFTs

We determine the supersymmetric AdS_7 backgrounds of seven-dimensional half-maximal gauged supergravities and show that they do not admit any deformations that preserve all 16 supercharges. We compare this result to the conformal manifold of the holographically dual (1,0) superconformal field theories and show that accordingly its representation theory implies that no supersymmetric marginal operators exist.Comment: 20 pages, corrected classification of non-semisimple gauge groups, version to appear in JHE

AdS5_5 vacua from type IIB supergravity on T1,1T^{1,1}

We study maximally supersymmetric Anti-de Sitter backgrounds in consistent N=2 truncations of type IIB supergravity compactified on the Sasaki-Einstein manifold $T^{1,1}$. In particular, we focus on truncations that contain fields coming from the nontrivial second and third cohomology forms on $T^{1,1}$. These give rise to N=2 supergravity coupled to two vector- and two hypermultiplets (Betti-vector truncation) or one vector- and three hypermultiplets (Betti-hyper truncation), respectively. We find that both truncations admit AdS$_5$ backgrounds with the gauge group always being broken but containing at least an $U(1)_R$ factor. Moreover, in both cases we show that the moduli space of AdS vacua is nontrivial and of maximal dimension. Finally, we explicitly compute the metrics on these moduli spaces.Comment: 20 pages; v2: updated references; v3: 21 pages, as published in JHE

Hiding the little hierarchy problem in the NMSSM

In this paper we consider a set of soft supersymmetry breaking terms within the NMSSM which leads to a small hierarchy between the supersymmetry breaking scale and the electroweak scale. Specifically only the gaugino masses and the soft term in the Higgs sector are non-vanishing at the GUT scale. This pattern can be found in gaugino mediated models and in higher-dimensional orbifold GUTs. We study the phenomenology of this scenario and find different low energy spectra depending on the Yukawa coupling $\lambda$ of the NMSSM singlet. In particular, for low values of $\lambda$ the singlet is the lightest scalar and the singlino is the LSP while for large values of $\lambda$ both are heavy and the gravitino can be the LSP. The singlet pseudoscalar is very light in the entire parameter space.Comment: Latex, 21+1 pages, 5 figures; v2: References and comments adde

Classification of maximally supersymmetric backgrounds in supergravity theories

We study maximally supersymmetric solutions of all gauged or deformed supergravity theories in $D \ge 3$ space-time dimensions. For vanishing background fluxes the space-time background has to be either Minkowski or anti-de Sitter. We derive a simple criterion for the existence of solutions with non-trivial fluxes and determine all supergravities that satisfy it. We show that their solutions coincide with those of the corresponding ungauged theories and conclude that the known list of maximally supersymmetric solutions is exhaustive.Comment: 25 pages; improved discussion of the gauged R-symmetry, references added, version to be published in JHE

Maximally Supersymmetric AdS4 Vacua in N=4 Supergravity

We study AdS backgrounds of N=4 supergravity in four space-time dimensions which preserve all sixteen supercharges. We show that the graviphotons have to form a subgroup of the gauge group that consists of an electric and a magnetic SO(3)_+ x SO(3)_-. Moreover, these N=4 AdS backgrounds are necessarily isolated points in field space which have no moduli.Comment: 11 page

Examples of N=2 to N=1 supersymmetry breaking

In this paper we consider gauged N=2 supergravities which arise in the low-energy limit of type II string theories and study examples which exhibit spontaneous partial supersymmetry breaking. For the quantum STU model we derive the scalar field space and the scalar potential of the N=1 supersymmetric low-energy effective action. We also study the properties of the Minkowskian N=1 supersymmetricground states for a broader class of supergravities including the quantum STU model.Comment: 22 pages, added references, version to appear in JHE