Abstract
This article discusses model-building scenarios including anti-D3-/D7-branes, in which supersymmetry is broken spontaneously, despite having no scale at which sparticles appear and standard supersymmetry is restored. If the branes are placed on singularities at the tip of warped throats in Calabi-Yau orientifold flux compactifications, they may give rise to realistic particle spectra, closed- and open-string moduli stabilisation with a Minkowski/de Sitter uplift, and a geometrical origin for the scale hierarchies. The paper derives the low-energy effective field theory description for such scenarios, i.e. a non-linear supergravity theory for standard and constrained supermultiplets, including soft supersymmetry-breaking matter couplings. The effect of closed-string moduli stabilisation on the open-string matter sector is worked out, incorporating non-perturbative and perturbative effects, and the mass and coupling hierarchies are computed with a view towards phenomenology.
Highlights
Supersymmetry has been a key ingredient of string theory model building and a leading candidate for a solution to the long-standing gauge hierarchy problem [1, 2]
Whilst the consistency of these de Sitter constructions is still under debate, the spontaneous breaking of supersymmetry by anti-D-branes means that these objects can be used in string model building whilst maintaining the powerful machinery of supersymmetry
This subsection begins with a brief general discussion on anti-D3-brane supersymmetry breaking and their low-energy effective field theory descriptions, the field content and action are described in detail
Summary
Supersymmetry has been a key ingredient of string theory model building and a leading candidate for a solution to the long-standing gauge hierarchy problem [1, 2]. Interesting bottom-up particle physics models may plausibly be embedded into complete string compactifications, with in principle all closed- and open-string moduli stabilised via fluxes, perturbative and non-perturbative effects Towards this objective, this article computes the low-energy effective field theory describing an anti-D3-/D7-brane system at an orbifold singularity at the tip of a strongly warped throat, within a supersymmetric type IIB Calabi-Yau orientifold flux compactification [4, 102,103,104,105]. By a dimensional reduction of the ten-dimensional and worldvolume actions, and by exploiting how the internal spacetime symmetries transform the intersecting states (for which no action is known), one can infer the non-linear supergravity action, encapsulated as usual in a Kähler potential, a superpotential, the gauge kinetic functions and the Fayet-Iliopoulos terms This non-linear supergravity theory allows one to infer the interactions related by supersymmetry, both linear and non-linear, and to work out the consequences of closed string moduli stabilisation, including perturbative and non-perturbative effects, on the open-string sectors. The appendices provide useful elements for the dimensional reduction of type IIB theories, a review of hidden-sector supersymmetry breaking and supergravity soft-breaking terms, and an extension of the latter in the presence of constrained superfields
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