Singlet Extensions of the MSSM in the Quiver Landscape

TL;DR

This paper explores string theory-based extensions of the MSSM with a singlet, identifying specific quiver models that satisfy key phenomenological constraints and can generate a dynamical mu-term.

Contribution

It systematically classifies quiver models in string theory that extend the MSSM with a singlet, satisfying phenomenological and string-theoretic constraints, and discusses moduli stabilization.

Findings

Identified three quiver models satisfying all constraints.

Demonstrated potential for D-instanton effects to generate superpotentials.

Addressed moduli stabilization issues in string-derived models.

Abstract

We map out possible extensions of the MSSM in the context of type II string theory. We systematically investigate three-stack and four-stack quivers which realize the MSSM spectrum with the addition of a single MSSM singlet S with an allowed S H_u H_d term, which can lead to a dynamical electroweak-scale mu-term. We present the three quivers which satisfy stringent string-theoretic and phenomenological constraints, including the presence of non-zero masses for all three families of quarks and leptons, the perturbative and non-perturbative absence of R-parity violating couplings and rapid dimension-five proton decay, and a mechanism for small neutrino masses. We find that these quivers can realize many models in the class of singlet-extended (supersymmetric) standard models, as D-instanton effects can in principle generate a superpotential of the form f(S), where f is a polynomial. Finally, we address the issue of the stabilization and decoupling of charged moduli which generically appear in D-instanton corrections to the superpotential.