Dynamical Supersymmetry Breaking in Standard-like Models with Intersecting D6-branes

TL;DR

This work studies dynamical supersymmetry breaking in a concrete N=1 Standard-like model built from a Type IIA ${\bf Z_2\times Z_2}$ orientifold with intersecting D6-branes. The authors identify a confining hidden sector ${USp(2)_A \times USp(2)_B \times USp(4)}$ that induces a leading non-perturbative superpotential via gaugino condensation, and they minimize the resulting moduli potential to obtain SUSY-breaking minima with the dilaton $S$ and a complex structure modulus $U$ fixed. The minima yield fixed gauge couplings at the string scale but a negative cosmological constant, and the resulting gaugino masses are highly non-universal and sensitive to the two moduli; the spectrum’s low-energy predictions for MSSM couplings are not realistic in this specific example. The paper argues that the qualitative mechanism—moduli fixing and SUSY breaking via gaugino condensation in intersecting D6-brane models—should extend to other similar constructions, potentially yielding more realistic vacua with further model-building refinements. Overall, the work provides a concrete realization of dynamical SUSY breaking in string-inspired Standard-like models and highlights the role of multiple moduli in determining gauge couplings and soft terms.

Abstract

We address dynamical supersymmetry breaking within a N=1 supersymmetric Standard-like Model based on a Z_2 x Z_2 Type IIA orientifold with intersecting D6-branes. The model possesses an additional, confining gauge sector with the USp(2)_A x USp(2)_B x USp(4) gauge group, where the gaugino condensation mechanism allows for the breaking of supersymmetry and stabilizes moduli. We derive the leading contribution to the non-perturbative effective superpotential and determine numerically the minima of the supergravity potential. These minima break supersymmetry and fix two undetermined moduli, which in turn completely specify the gauge couplings at the string scale. For this specific construction the minima have a negative cosmological constant. We expect that for other supersymmetric Standard-like models with intersecting D6-branes, which also possess confining gauge sectors, the supersymmetry breaking mechanism would have qualitatively similar features.

Figures (1)

• Figure 1: Plots of potential $V$ (in units of $\Lambda^2\equiv [\sqrt{6}\Lambda^3/(32\pi^2e)]^2$) as a function of $Re(S)$ and $Re(U)$ ($Im(U)=1.91$ and $Im(S)=0.48$), $Re(S)$ and $Im(S)$ ($Re(U)=0.575$ and $Im(U)=1.91$), and $Re(U)$ and $Im(U)$ ($Re(S)=1.10$ and $Im(S)=0.48$), respectively. In the Figures $Re(S), \ Im(S), \ Re(U)$, and $Im(U)$ are denoted $sr,\ si, \ ur, \ ui$, respectively.