LMA solution to the solar neutrino problem and a phenomenological charged lepton mass matrix

We propose a phenomenological form of the charged lepton mass matrix which extends the idea of a ”lopsided” mass matrix found in the literature. The features of the form are that both the 2-3 and 1-3 elements of the charged lepton mass matrix are of order 1 and that the small elements have a new structure. This form leads to the interesting result that both large atmospheric and solar neutrino mixing can be accounted for by the matrix. Another interesting result of this mass matrix is that it leads to very small 1-3 mixing in the lepton sector and can suppress the branching ratio of under the present experimental limit in the supersymmetric see-saw case. Received: 3 October 2002 / Revised version: 10 November 2002 / Published online: 24 January 2003 RID="a" ID="a" e-mail: bixj@mail.tsinghua.edu.cn RID="b" ID="b" e-mail: dyb@itp.ac.cn