Stringy surprises

TL;DR

This paper discusses a string theory approach based on higher-dimensional grand unification that naturally yields MSSM-like models with realistic features, without manual tuning, highlighting unexpected 'stringy surprises'.

Contribution

It presents a method for deriving MSSM models from string theory with automatic realization of key phenomenological features.

Findings

Models exhibit see-saw suppressed neutrino masses

Models have an order one top Yukawa coupling

Models include a hidden sector with TeV-scale strong dynamics

Abstract

There are many conceivable possibilities of embedding the MSSM in string theory. These proceedings describe an approach which is based on grand unification in higher dimensions. This allows one to obtain global string-derived models with the exact MSSM spectrum and built-in gauge coupling unification. It turns out that these models exhibit various appealing features such as (i) see-saw suppressed neutrino masses, (ii) an order one top Yukawa coupling and potentially realistic flavor structures, (iii) non-Abelian discrete flavor symmetries relaxing the supersymmetric flavor problem, (iv) a hidden sector whose scale of strong dynamics is consistent with TeV-scale soft masses, and (v) a solution to the mu-problem. The crucial and unexpected property of these features is that they are not put in by hand nor explicitly searched for but happen to occur automatically, and might thus be viewed as "stringy surprises".