Flux-induced SUSY-breaking soft terms on D7-D3 brane systems
P. G. Camara, L. E. Ibanez, A. M. Uranga
TL;DR
This work analyzes the impact of RR and NSNS 3-form fluxes on Type IIB D7/D3-brane configurations, focusing on D7-branes wrapping 4-cycles. By deriving the 8d D7 action in flux backgrounds and performing a careful 4d reduction, the authors show that ISD fluxes induce nonzero SUSY-breaking soft terms on D7-brane worldvolumes, including gaugino and scalar masses and trilinears, while certain D3-brane terms respond differently. They map these results to an effective 4d supergravity description, revealing a symmetry between D3 and D7 sectors and highlighting a positive definite scalar potential in ISD backgrounds. The analysis extends to D3-D7 intersections, multiple geometric moduli, and more general local geometries (e.g., K3), and discusses concrete MSSM-like constructions at orbifolds and implications for KKLT moduli stabilization and de Sitter vacua. Overall, the paper establishes a controlled framework where fluxes stabilize brane moduli and generate calculable SUSY-breaking terms with potential phenomenological relevance.
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.