====== TTP02-12 On the hierarchy of neutrino masses ======
 
 
   <hidden TTP02-12  On the hierarchy of neutrino masses >   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 U_e3 is a consequence of the model. The
 masses of the active neutrinos are given by $\mu_3\approx\sqrt{\Delta m_{@}^2}$
 and $\mu_1/\mu_2\approx \tan^2\theta_\odot$.
 </hidden>
|**M. Jezabek and P. Urban**  | 
|**  Acta Phys.Polon.  B33 2571-2584 2002  **  |
| {{preprints:2002:ttp02-12.pdf|PDF}} {{preprints:2002:ttp02-12.ps|PostScript}} [[http://arxiv.org/abs/hep-ph/0207018|arXiv]]   |
| |