Leptonic CP violation in flipped SU(5) GUT from Z 12−I orbifold compactification

Abstract

We obtain a phenomenologically acceptable PMNS matrix in a flipped SU(5) model, possessing the Z 4R discrete symmetry, from the compactification of heterotic string E 8 ×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 |δ PMNS |≲63 o for the normal hierarchy of neutrino masses with the PDG book parametrization. © 2019 The Author(s)