We present a determination of the neutrino mass matrix which holds for values
of the neutrinoless double beta decay effective mass m_{ee} larger than the
neutrino mass differences. We find eight possible solutions and discuss for
each one the corresponding neutrino mass eigenvalues and zero texture. A
minimal structure of the perturbations to add to these zero textures to recover
the full mass matrix is also determined. Implications for neutrino hot dark
matter are discussed for each solution.Comment: 18 page
