2008/04/30 by Carl H. Albright, Werner Rodejohann
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Neutrino Physics Research #Particle physics theoretical and experimental studies #hep-ph
paper · pdf · doi:10.1016/j.physletb.2008.06.044
published as Phys.Lett.B665:378-383,2008 · 14 pages, 8 figures. Typos corrected, references added. To appear in PLB
arxiv created 2008/06/17 · openalex publication_date 2008/06/27 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
To address the issue of whether tri-bimaximal mixing (TBM) is a softly-broken hidden or an accidental symmetry, we adopt a model-independent analysis in which we perturb a neutrino mass matrix leading to TBM in the most general way but leave the three texture zeros of the diagonal charged lepton mass matrix unperturbed. We compare predictions for the perturbed neutrino TBM parameters with those obtained from typical SO ( 10 ) grand unified theories with a variety of flavor symmetries. Whereas SO ( 10 ) GUTs almost always predict a normal mass hierarchy for the light neutrinos, TBM has a priori no preference for neutrino masses. We find, in particular for the latter, that the value of | U e 3 | is very sensitive to the neutrino mass scale and ordering. Observation of | U e 3 | 2 > 0.001 to 0.01 within the next few years would be incompatible with softly-broken TBM and a normal mass hierarchy and would suggest that the apparent TBM symmetry is an accidental symmetry instead. No such conclusions can be drawn for the inverted and quasi-degenerate hierarchy spectra.