Perturbativity and a Fourth Generation in the MSSM

TL;DR

This paper explores extending the MSSM with a fourth generation, finding it challenges perturbativity up to the GUT scale, and proposes a model with additional vector-like states to maintain perturbativity.

Contribution

It introduces a model with vector-like states that preserves perturbativity in the MSSM extended with a fourth generation.

Findings

Fourth generation in MSSM disrupts perturbativity up to GUT scale.

Adding vector-like states at TeV scale restores perturbativity.

The proposed model maintains perturbative unification up to GUT scale.

Abstract

We study an extension of the MSSM with a fourth generation of chiral matter. With this extension no value of $\tb$ allows the theory to stay perturbative up to the GUT scale. We suggest one model with extra vector-like states at the TeV scale that allows perturbativity all the way up to the GUT scale.