Hall, LJ; Smith, D, *Leading order textures for lepton mass matrices*,
Physical Review D - Particles, Fields, Gravitation and Cosmology, vol. 59 no. 11
(1999),
pp. 1-9 .
**Abstract:**

*In theories with three light neutrinos, certain simplicity assumptions allow the construction of a complete list of leading order lepton mass matrices. These matrices are consistent with mτ≠0,Δm122≪Δm 232,θ23∼O(1) and θ13=0, as suggested by measurements of atmospheric and solar neutrino fluxes. The list contains twelve generic cases: two have three degenerate neutrinos, eight have two neutrinos forming a Dirac state, and in only two cases is one neutrino much heavier than the other two. For each of these twelve generic cases the possible forms for the perturbations which yield mμ are given. Ten special textures are also found. ©1999 The American Physical Society.*