Neutrino mass ordering and μ-τ reflection symmetry breaking

Abstract

If the neutrino mass spectrum turns out to be m^{}_3 < m^{}_1 < m^{}_2, one\nmay choose to relabel it as m^{\\prime}_1 < m^{\\prime}_2 < m^{\\prime}_3 such\nthat all the masses of fundamental fermions with the same electrical charges\nare in order. In this case the columns of the 3\\times 3 lepton flavor mixing\nmatrix U should be reordered accordingly, and the resulting pattern U^\\prime\nmay involve one or two large mixing angles in the standard parametrization or\nits variations. Since the Majorana neutrino mass matrix keeps unchanged in such\na mass relabeling, a possible \\mu-\\tau reflection symmetry is respected in this\nconnection and its breaking effects are model-independently constrained at the\n3\\sigma level by using current experimental data.\n