Aspects of Nonrenormalizable Terms in a Superstring Derived Standard--like Model

TL;DR

This paper examines the impact of nonrenormalizable terms in a superstring-derived model, showing how they influence gauge symmetry, supersymmetry breaking, and fermion mass hierarchy.

Contribution

It reveals how nonrenormalizable terms restrict gauge symmetry and affect supersymmetry breaking, providing a framework for realistic fermion mass hierarchies.

Findings

Nonrenormalizable terms limit gauge symmetry to SU(3)×SU(2)×U(1)_{B-L}×U(1)_{T_{3_R}}.

Direct symmetry breaking to the Standard Model can break supersymmetry at the Planck scale.

A hierarchical fermion mass spectrum can be generated within the model.

Abstract

I investigate the role of nonrenormalizable terms, up to order N=8, in a superstring derived standard--like model. I argue that nonrenormalizable terms restrict the gauge symmetry, at the Planck scale, to be $SU(3)\times SU(2)\times U(1)_{B-L}\times U(1)_{T_{3_R}}$ rather than $SU(3)\times SU(2)\times U(1)_Y$. I show that breaking the gauge symmetry directly to the Standard Model leads to breaking of supersymmetry at the Planck scale, or to dimension four, baryon and lepton violating, operators. I show that if the gauge symmetry is broken directly to the Standard Model the cubic level solution to the F and D flatness constraints is violated by higher order terms, while if $U(1)_{Z^\prime}$ remains unbroken at the Planck scale, the cubic level solution is valid to all orders of nonrenormalizable terms. I discuss the Higgs and fermion mass spectrum. I demonstrate that realistic, hierarchical, fermion mass spectrum can be generated in this model.