Exact Standard Model Structures from Intersecting Branes

TL;DR

This paper presents string theory models using intersecting D6 branes that precisely reproduce the Standard Model at low energies, with realistic phenomenological features including neutrino masses and proton stability.

Contribution

It introduces novel non-supersymmetric string constructions based on intersecting D6 branes that exactly realize the Standard Model without extra matter or gauge groups.

Findings

Models exhibit a stable proton.

Neutrino masses align with oscillation data.

Existence of supersymmetric particles in non-SUSY models.

Abstract

I discuss two types of non-supersymmetric string model constructions that give at low energy exactly the Standard model (SM) with no additional matter/and or gauge group factors. The construction is based on D6 branes intersecting at angles in a compactification of type IIA theory on a decomposable orientifolded $T^6$ torus. The first type is based on five and six stack SM-like constructions at the string scale while, the other construction is based on a four stack GUT left-right symmetric structure centered around the Pati-Salam $SU(4)_C \times SU(2)_L \times SU(2)_R$ gauge group. All classes of models exbibit important phenomenological properties including a stable proton and sizes of neutrino masses in consistency with neutrino oscillation experiments. The models are non-SUSY, but amazingly, they allow the existence of supersymmetric particles!