1999/04/13 by John Ellis, Smaragda Lola · 7 citations
Physics and Astronomy · #Dark Matter and Cosmic Phenomena #Neutrino Physics Research #Particle physics theoretical and experimental studies #astro-ph #hep-ex #hep-ph
paper · pdf · doi:10.1016/s0370-2693(99)00545-6
published as Phys.Lett.B458:310-321,1999 · 17 pages, 4 figures. Corrections to typos and notation: rephrased and clarified statements on impact of induced deviations from bimaximal mixing
arxiv created 1999/04/13 · openalex publication_date 1999/07/01 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We reconsider the possibility that the masses of the three light neutrinos of the Standard Model might be almost degenerate and close to the present upper limits from Tritium beta decay and cosmology. In such a scenario, the cancellations required by the latest upper limit on neutrinoless double-beta decay enforce near-maximal mixing that may be compatible only with the vacuum-oscillation scenario for solar neutrinos. We argue that the mixing angles yielded by degenerate neutrino mass-matrix textures are not in general stable under small perturbations. We evaluate within the MSSM the generation-dependent one-loop renormalization of neutrino mass-matrix textures that yielded degenerate masses and large mixing at the tree level. We find that mnue > mnumu > mnutau after renormalization, excluding MSW effects on solar neutrinos. We verify that bimaximal mixing is not stable, and show that the renormalized masses and mixing angles are not compatible with all the experimental constraints, even for tanbeta as low as unity. These results hold whether the neutrino masses are generated by a see-saw mechanism with heavy neutrinos weighing approx. 1013 GeV or by non-renormalizable interactions at a scale approx. 105 GeV. We also comment on the corresponding renormalization effects in the minimal Standard Model, in which mnue < mnumu < mnutau. Although a solar MSW effect is now possible, the perturbed neutrino masses and mixings are still not compatible with atmospheric- and solar-neutrino data.