Moduli stabilization and SUSY breaking in heterotic orbifold string models

TL;DR

The paper tackles moduli stabilization and SUSY breaking in the heterotic orbifold mini-landscape, aiming to realize MSSM-like physics with stabilized moduli. It implements a minimal setup with a single gaugino-condensing hidden sector and an anomalous U(1)_A that uplifts the vacuum, while modular invariance and twisted-sector dynamics stabilize the full moduli space, including blow-up moduli. The resulting low-energy spectrum features gravity-dominated soft terms with a mostly bino LSP and TeV-scale superpartners, offering LHC-relevant phenomenology, though cosmological issues such as gravitino and moduli problems are acknowledged. Overall, the work presents a relatively economical moduli-stabilization mechanism in heterotic orbifolds that yields concrete, testable predictions and clarifies how exotics decouple in the stabilized vacuum.

Abstract

In this paper we discuss the issues of supersymmetry breaking and moduli stabilization within the context of E_8 x E_8 heterotic orbifold constructions and, in particular, we focus on the class of "mini-landscape" models. In the supersymmetric limit, these models admit an effective low energy field theory with a spectrum of states and dimensionless gauge and Yukawa couplings very much like that of the MSSM. These theories contain a non-Abelian hidden gauge sector which generates a non-perturbative superpotential leading to supersymmetry breaking and moduli stabilization. We demonstrate this effect in a simple model which contains many of the features of the more general construction. In addition, we argue that once supersymmetry is broken in a restricted sector of the theory, then all moduli are stabilized by supergravity effects. Finally, we obtain the low energy superparticle spectrum resulting from this simple model.

Figures (3)

• Figure 1: As ${\rm Re}\,T \rightarrow \infty$, the potential for $b_i > 0$ mimics a Racetrack, which can be seen from Eqn. (\ref{['model_superpotential']}), for example. In the case where $b_i < 0$, however, the potential exhibits a different asymptotic behavior. As ${\rm Re}\,T \rightarrow \infty$ the potential diverges, which means that theory is forced to be compactified Font:1990ntCvetic:1991qm.
• Figure 2: The scalar potential in the $\text{Re} \ S$ direction for Case 2.
• Figure 3: The one loop Coleman-Weinberg potential (Case 4) for $\phi_2$. The dashed line represents the VEV of $\phi_2$ in the minimum of the full potential.