# Unification and Fermion Mass Structure

## TL;DR

This paper updates GUT-scale fermion mass and mixing data within the MSSM framework, revealing that classic mass relations are not always maintained, but can be corrected at large tan beta with specific threshold effects.

## Contribution

It provides updated GUT-scale mass and mixing angle values and explores conditions under which traditional GUT mass relations hold or are corrected.

## Key findings

- Classic GUT mass relations fail at small to moderate tan beta.
- Large tan beta can restore relations via threshold corrections.
- Discrepancies depend on the sign of gluino and wino masses.

## Abstract

Grand Unified Theories predict relationships between the GUT-scale quark and lepton masses. Using new data in the context of the MSSM, we update the values and uncertainties of the masses and mixing angles for the three generations at the GUT scale. We also update fits to hierarchical patterns in the GUT-scale Yukawa matrices. The new data shows not all the classic GUT-scale mass relationships remain in quantitative agreement at small to moderate tan beta. However, at large tan beta, these discrepancies can be eliminated by finite, tan beta-enhanced, radiative, threshold corrections if the gluino mass has the opposite sign to the wino mass.