Flux-induced SUSY-breaking soft terms on D7-D3 brane systems

TL;DR

This paper investigates how RR and NSNS 3-form fluxes influence the effective action and SUSY-breaking soft terms in D7-D3 brane systems within Type IIB string theory, with implications for moduli stabilization and MSSM-like model building.

Contribution

It extends previous analyses to D7-branes, explicitly computes flux effects on worldvolume fields, and explores SUSY-breaking soft terms in D3-D7 configurations, including MSSM-like models.

Findings

Fluxes stabilize some or all D7-brane moduli.

(0,3) fluxes induce SUSY-breaking soft terms.

Constructed MSSM-like models at orbifold singularities.

Abstract

We study the effect of RR and NSNS 3-form fluxes on the effective action of the worldvolume fields of Type IIB D7/D3-brane configurations. The D7-branes wrap 4-cycles on a local Calabi-Yau geometry. This is an extension of previous work on hep-th/0311241, where a similar analysis was applied to the case of D3-branes. Our present analysis is based on the D7- and D3-brane Dirac-Born-Infeld and Chern-Simons actions, and makes full use of the R-symmetries of the system, which allow us to compute explicitly results for the fields lying at the D3-D7 intersections. A number of interesting new properties appear as compared to the simpler case of configurations with only D3-branes. As a general result one finds that fluxes stabilize some or all of the D7-brane moduli. We argue that this is important for the problem of stabilizing Kahler moduli through non-perturbative effects in KKLT-like vacua. We also show that (0,3) imaginary self-dual fluxes, which lead to compactifications with zero vacuum energy, give rise to SUSY-breaking soft terms including gaugino and scalar masses, and trilinear terms. Particular examples of chiral MSSM-like models of this class of vacua, based on D3-D7 brane systems at orbifold singularities are presented.