Neutrino mass matrix suppression by Abelian charges with see-saw mechanism

We have investigated a neutrino mass matrix model without supersymmetry inc luding three seesaw right-handed neutrinos around order 10(12) GeV masses, aiming at a picture with all small numbers explained as being due to approx imately conserved gauge charges. The prediction of the solar neutrino mixin g angle is given by sin(2) 2 theta (circle dot) = 3(-2)(+3) x 10(-2); in fa ct, the solar mixing angle is, apart from detailed order unity corrections, equal to the Cabibbo angle. Furthermore the ratio of the solar neutrino ma ss square difference to that for the atmospheric neutrino oscillation is pr edicted to 6(-4)(+11) x 10(-4) and is given by the same Cabibbo angle relat ed parameter xi as 6 xi (4). (C) 2000 Elsevier Science B.V. All rights rese rved.