Non-supersymmetric string models from anti-D3-/D7-branes in strongly warped throats

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.

Standard model from a supergravity model with a naturally small cosmological constant

“…This further suggests that the SM particles are simply open string modes inside the D3-brane (or a stack of p ≥ 5 of them that span our 3-dimensional observable universe) [4], or more generally, inside a D3/D7 system, with a set of intersecting D7-branes. Similar scenarios have been suggested earlier [9][10][11][12][13][14]. In this paper, the naturalness criterion (1.1) provides crucial guidance in developing the model.…”

The gravitino and the swampland

“…The use of anti-branes, as first considered for uplift, inflation and brane supersymmetry breaking in[67- 69], has been under severe scrutiny during the last years. On the one hand, considerable progress has been made in the understanding of the correct description at the EFT level in terms of non-linear supersymmetry with constrained superfields[70][71][72][73][74][75][76][77][78][79]. On the other hand, possible issues have been identified when using warped throats[52,53,80], which are useful to create energy hierarchies and redshift the tension of the anti-branes.…”

Misaligned supersymmetry and open strings

“…We are studying here an analogous flat-space model and discover a surprising connection to misaligned supersymmetry. More generically, non-supersymmetric branes lead to four-dimensional low energy effective theories with broken supersymmetry, which constitute a much wider class of models than supersymmetric ones [27] and could lead to phenomenologically interesting non-supersymmetric realisations of the Standard Model [28,29]. These are the motivations why we decided to revisit and investigate further anti-Dp-branes and Op-planes in string theory, uncovering their connection to misaligned supersymmetry.…”