There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.
Abstract
A possible interplay of both terms in the type II see-saw formula is illustrated by
presenting a novel way to generate deviations from exact bimaximal neutrino mixing.
In type II see-saw mechanism with dominance of the non-canonical SU(2)_L triplet term,
the conventional see-saw term can give a small contribution to the neutrino mass matrix.
If the triplet term corresponds to the bimaximal mixing scheme in the normal hierarchy,
the small contribution of the conventional see-saw term naturally generates non-maximal
solar neutrino mixing. Atmospheric neutrino mixing is also reduced from maximal, corresponding
to 1 - \sin^2 2 \theta_{23} of order 0.01. Also, small but non-vanishing U_{e3} of
order 0.001 is obtained. It is also possible that the \Delta m^2 responsible for solar
neutrino oscillations is induced by the small conventional see-saw term. Larger deviations
from zero U_{e3} and from maximal atmospheric neutrino mixing are then expected. This
scenario links the small ratio of the solar and atmospheric \Delta m^2 with the deviation
from maximal solar neutrino mixing. We comment on leptogenesis in this scenario and
compare the contributions to the decay asymmetry of the heavy Majorana neutrinos as
induced by themselves and by the triplet.