Effects of intermediate scales on renormalization group running of fermion observables in an SO(10) model

TL;DR

This paper investigates how intermediate energy scales in non-supersymmetric SO(10) models affect the renormalization group evolution of fermion masses and mixings, highlighting significant deviations from simpler models.

Contribution

It introduces a numerical nested sampling method to analyze the impact of an intermediate Pati--Salam scale on fermion observables in SO(10) models.

Findings

Intermediate scales cause sizable deviations in fermion masses and mixings.

The nested sampling approach effectively explores the parameter space.

Results align with experimental data when intermediate effects are included.

Abstract

In the context of non-supersymmetric SO(10) models, we analyze the renormalization group equations for the fermions (including neutrinos) from the GUT energy scale down to the electroweak energy scale, explicitly taking into account the effects of an intermediate energy scale induced by a Pati--Salam gauge group. To determine the renormalization group running, we use a numerical minimization procedure based on a nested sampling algorithm that randomly generates the values of 19 model parameters at the GUT scale, evolves them, and finally constructs the values of the physical observables and compares them to the existing experimental data at the electroweak scale. We show that the evolved fermion masses and mixings present sizable deviations from the values obtained without including the effects of the intermediate scale.