A Simple Grand Unified Relation between Neutrino Mixing and Quark Mixing

TL;DR

This paper proposes a unified framework linking quark and neutrino mixing via vectorlike fermions, predicting neutrino parameters and CP phases with a simple model based on SU(5) symmetry.

Contribution

It introduces a model where all flavor mixing arises from fermion mixing with vectorlike states, unifying quark and neutrino mixing matrices and predicting neutrino parameters.

Findings

Predicted neutrino mixing angles consistent with data.

Estimated leptonic CP phase slightly greater than pi.

Derived a simple expression for the neutrino mass matrix.

Abstract

It is proposed that all flavor mixing is caused by the mixing of the three quark and lepton families with vectorlike fermions in 5 + 5-bar multiplets of SU(5). This simple assumption implies that both V_{CKM} and U_{MNS} are generated by a single matrix. The entire 3-by-3 complex mass matrix of the neutrinos M_{nu} is then found to have a simple expression in terms of two complex parameters and an overall scale. Thus, all the presently unknown neutrino parameters are predicted. The best fits are for theta_{atm} less than or approximately 40 degrees. The leptonic Dirac CP phase is found to be somewhat greater than pi radians.