# Leptonic CP violation in flipped SU(5) GUT from $Z_{12-I}$ Orbifold Compactification

## TL;DR

This paper constructs a flipped SU(5) GUT model from string compactification that produces a realistic PMNS matrix and explores leptonic CP violation, including the Jarlskog determinant and CP phase constraints.

## Contribution

It presents a string-inspired flipped SU(5) model with a phenomenologically viable PMNS matrix and analyzes leptonic CP violation using the Kim-Seo form.

## Key findings

- PMNS matrix compatible with experimental data
- CP phase |4_{
m PMNS}|  64b0 for normal hierarchy
- Efficient analysis of Jarlskog determinant in the model

## Abstract

We obtain a phenomenologically acceptable PMNS matrix in a flipped SU(5) model inspired by the compactification of heterotic string $E_8\times E_8'$. To analyze the Jarlskog determinant efficiently, we include the simple Kim-Seo form for the Pontecorbo-Maki-Nakagawa-Sakata matrix. We also noted that $|\delta_{\rm PMNS}|\lesssim 64^{\rm o}$ for the normal hierarchy of neutrino masses with the PDG book parametrization.