The Elements of the Neutrino Mass Matrix: Allowed Ranges and   Implications of Texture Zeros
  We study the range of the elements of the neutrino mass matrix m_nu in the charged lepton basis. Neutrino-less double beta decay is sensitive to the ee element of m_nu. We then analyze the phenomenological implications of single texture zeros. In particular, interesting predictions for the effective mass can be obtained, in the sense that typically only little cancellation due to the Majorana phases is expected. Some cases imply constraints on the atmospheric neutrino mixing angle. 
A. Merle, W. Rodejohann