English

Normal vs. Inverted Hierarchy in Type I Seesaw Models

High Energy Physics - Phenomenology 2009-11-10 v2 High Energy Physics - Experiment

Abstract

We demonstrate that, for every grand unified model based on a conventional type I seesaw mechanism leading to a normal light neutrino mass hierarchy, one can easily generate a corresponding model with an inverted hierarchy which yields the same neutrino oscillation parameters. However, the latter type model has several unattractive instabilities which will disfavor any grand unified type I seesaw model, if an inverted neutrino mass hierarchy is observed experimentally. This should be contrasted with the softly-broken LeLμLτL_e - L_\mu - L_\tau flavor symmetry models which are eliminated, if the data favors a normal mass hierarchy.

Keywords

Cite

@article{arxiv.hep-ph/0407155,
  title  = {Normal vs. Inverted Hierarchy in Type I Seesaw Models},
  author = {Carl H. Albright},
  journal= {arXiv preprint arXiv:hep-ph/0407155},
  year   = {2009}
}

Comments

10 pages including 1 figure; improved version with additional illustration of results for whole class of models with charged lepton mass matrices diagonal in flavor space; accepted for publication in Physics Letters B

R2 v1 2026-07-22T13:55:58.480Z