Neutrino masses and mixing angles in a realistic string-inspired model - art. no. 095004

We analyze a supersymmetric string-inspired model of all fermion masses and mixing angles based on the Pati-Salam SU(4)xSU(2)(L)xSU(2)(R) gauge group supplemented by a U(1)(x) flavor symmetry. The model involves third family Yukawa unification and predicts the top quark mass and the ratio of the vac uum expectation values tan beta. The model also provides a successful descr iption of the CKM matrix and predicts the masses of the down and strange qu arks. However, our main focus is on the neutrino masses and MNS mixing angl es, and we show how the recent atmospheric neutrino mixing observed by Supe r-Kamiokande and the MSW solution to the solar neutrino problem lead to imp ortant information about the flavor structure of the model near the string scale. We show how single right-handed neutrino dominance may be implemente d by the use of "Clebsch zeros," leading to the LMA MSW solution, correspon ding to bimaximal mixing. The LOW MSW and SMA MSW solutions are also discus sed.