2002/07/01 by M. Jezabek, P. Urban
Physics and Astronomy · #hep-ph
published as Acta Phys.Polon. B33 (2002) 2571-2584 · 12 pages; Talk presented by M. Jezabek at 'Supersymmetry and Brane Worlds,' Fifth European Meeting Planck 02, Kazimierz, Poland, May 25-29, 2002, to appear in Acta Phys. Polon. B
arxiv created 2002/07/01 · arxiv updated 2009/11/30
We present a model of neutrino masses combining the seesaw mechanism and strong Dirac mass hierarchy and at the same time exhibiting a significantly reduced hierarchy at the level of active neutrino masses. The heavy Majorana masses are assumed to be degenerate. The suppression of the hierarchy is due to a symmetric and unitary operator R whose role is discussed. The model gives realistic mixing and mass spectrum. The mixing of atmospheric neutrinos is attributed to the charged lepton sector whereas the mixing of solar neutrinos is due to the neutrino sector. Small Ue3 is a consequence of the model. The masses of the active neutrinos are given by μ3≈√Δm@2 and μ1/μ2≈ tan2θ_\odot.