Understanding structures and symmetries of the neutrino mass matrix

by Michele Frigerio (UC Riverside)

Friday 25 Jun 2004, 14:00 → 15:00 Europe/Zurich

TH Auditorium (CERN)

I reconstruct the neutrino mass matrix M, using the experimental data on neutrino oscillations, as well as upper bounds on neutrino masses. For the different possible mass spectra, I discuss the dependence of the matrix structure on the Dirac and Majorana CP-violating phases. The role of neutrinoless 2β-decay is emphasized. I analyse the theoretical relevance of the maximal atmospheric mixing and the difficulties to generate it with a flavour symmetry. It turns out that the permutation group S₃ is suitable to explain this mixing and all other basic features of the Standard Model flavour sector. I construct a minimal model based on S₃ which reproduces data and predicts a number of testable relations among observables.