Local Grand Unification and String Theory

TL;DR

This paper explores how local grand unification in string theory, influenced by compactification and field localization, can explain key features of the MSSM and address several fundamental problems in particle physics.

Contribution

It introduces the concept of local grand unification in string theory and discusses its implications for the MSSM and related phenomenological issues.

Findings

Enhanced discrete symmetries near orbifold fixed points

Implications for proton stability and flavor structure

Potential solutions to the -problem and strong CP-problem

Abstract

The low energy effective action of string theory depends strongly on the process of compactification and the localization of fields in extra dimensions. Explicit string constructions towards the minimal supersymmetric standard model (MSSM) reveal interesting results leading to the concept of local grand unification. Properties of the MSSM indicate that we might live at a special location close to an orbifold fixed point rather than a generic point in Calabi-Yau moduli space. We observe an enhancement of (discrete) symmetries that have various implications for the properties of the MSSM such as proton stability as well as solutions to the flavor problem, the \mu-problem and the strong CP-problem.