Majorana neutrino mass matrix with CP symmetry breaking
  From the new existing data with not vanishing theta13 mixing angle we determine the possible shape of the Majorana neutrino mass matrix. We assume that CP symmetry is broken and all Dirac and Majorana phases are taken into account. Two possible approaches "bottom-up" and "top down" are presented. The problem of unphysical phases is examined in detail. 
Bartosz Dziewit, Sebastian Zajac, Marek Zralek
hep-ph