SUSY-breaking Soft Terms in a MSSM Magnetized D7-brane Model

TL;DR

This work computes SUSY-breaking soft terms in a MSSM-like model built from magnetized D7-branes in Type IIB string theory, using an effective ${ m obreakspace} { m obreakspace} \\mathcal{N}=1$ supergravity framework with nonzero auxiliary fields for the dilaton and Kähler moduli. It provides explicit structures for the Kähler potential, gauge kinetic functions, and superpotential, and derives the soft terms for different SUSY-breaking sources, notably ISD (T-dominance) and IASD/dilaton scenarios, including a flux-parameter $oldsymbol{ u}$ that encodes magnetic flux effects. The results show flavor-universal scalar masses and gaugino masses with dependence on $m_{3/2}$, the goldstino angle, and flux parameters; dilaton-dominated breaking can induce tachyons unless fluxes are substantial, while T-dominance yields tachyon-free, simple relations, especially in the diluted flux limit. The authors discuss the implications for realizing realistic softness in toroidal versus Calabi–Yau/F-theory embeddings and suggest that hierarchical soft terms may emerge in more general CY settings, providing a link to previous analyses and motivating further geometric refinements. Overall, the work connects explicit D-brane constructions to phenomenologically relevant SUSY-breaking patterns and clarifies how magnetic flux and moduli F-terms shape the low-energy soft spectrum.

Abstract

We compute the SUSY-breaking soft terms in a magnetized D7-brane model with MSSM-like spectrum, under the general assumption of non-vanishing auxiliary fields of the dilaton and Kahler moduli. As a particular scenario we discuss SUSY breaking triggered by ISD or IASD 3-form fluxes.