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

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.

Standard coupling unification in SO(10), hybrid seesaw neutrino mass and leptogenesis, dark matter, and proton lifetime predictions

“…As pointed out in section 1, χ 2 fit to all fermion masses and mixings in SUSY SO(10) or in non-SUSY SO(10) with G 224 intermediate symmetry requires a small departure from this assumption [69,137,139,140]. On the other hand a very recent derivation of neutrino mass and mixing sum-rules has been found to require M D close to M u [141] as in our case.…”

“…Extensive investigations in such models have been reported with high intermediate scales [69,[129][130][131][132][133][134][135][136][137][138][139][140][141] and also with TeV scale W R , Z R bosons and verifiable seesaw mechanisms [142][143][144][145][146][147][148][149][150][151][152][153]. Out of a large number of possible models that are predicted from non-SUSY SO(10) [132] fermion mass fit has been investigated only in one class of models with Pati-Salam intermediate symmetry [69,137,139,140] and also including additional vector-like fermions [138]. The issue of DM has been also addressed with different types of high scale intermediate symmetries and by introducing additional fermions or scalars beyond those needed by extended survival hypothesis [154][155][156][157][158] but without addressing fermion mass fits.…”

Unification, proton decay, and topological defects in non-SUSY GUTs with thresholds

“…Also, the different breaking patterns lead to different phenomenological models at low energy, as discussed in [14,24,25,[28][29][30][31] for SO (10) and [17,20,21,[32][33][34][35][36][37][38][39][40][41][42][43] for E (6). The neutrino and charged fermion mass and mixing generation in the context of unified theories are discussed in [24,[44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61]. In [62][63][64][65][66][67]…”

Running of fermion observables in non-supersymmetric SO(10) models

“…In this section, we describe the procedure and numerical tools used to perform the parameter fits, which follows closely refs. [14,17]. The general procedure consists of minimizing a χ 2 function, which is formed by comparing measured data at M Z with the RG running of parameter values from M GUT to M Z in a given SO (10) In order to determine the values of the above-mentioned parameters that provide the best fit to measured data, we employ the following strategy: 3.…”

“…The present work aims to extend the analysis of the two models in refs. [14,17] in several ways. Firstly, we fit to the two neutrino mass-squared differences separately, whereas the above mentioned works performed the fits to only their ratio.…”