The Majorana neutrino mass matrix indicated by the current data

The Majorana neutrino mass matrix combines information from the neutrino masses and the leptonic mixing in the flavor basis. Its invariance under some transformation matrices indicates the existence of certain residual symmetry. We offer an intuitive display of the structure of the Majorana neutrino mass matrix, using the whole set of the oscillation data. The structure is revealed depending on the lightest neutrino mass. We find that there are three regions with distinct characteristics of structure. A group effect and the mu-tau exchange symmetry are observed. Six types of texture non-zeros are shown. Implications for flavor models are discussed.National Natural Science Foundation of China [11035003, 11120101004]SCI(E)EI中国科学引文数据库(CSCD)ARTICLEmabq@pku.edu.cn7071002-1-071002-135