Radiative Neutrino Masses in a SUSY GUT Model

Radiatively-induced neutrino mass matrix is investigated within the framework of an SU(5) SUSY GUT model. The model has matter fields of three families 5L(+)i +5L(+)i in addition to the ordinary matter fields 5L(−)i +10L(+)i and Higgs fields H(+)+H(0), where (+, 0,−) denote the transformation properties (ω, ω, ω) (ω = +1) under a discrete symmetry Z3. R-parity violating terms are given by 5L(+)5L(+)10L(+), while the Yukawa interactions are given by H(0)5L(−)10L(+), i.e. the 5-fields in both are different from each other. The Z3 symmetry is only broken by the terms 5L(+)i5L(+)i softly, so that the 5L(+)i ↔ 5L(−)i mixings appear at μ < MX . Of the R-parity violating terms 5L(+)5L(+)10L(+), only the terms (eLν−νLe)e c R sizably appear at μ < MX . PACS numbers: 14.60.Pq; 12.60.Jv; 11.30.Hv; 11.30.Er;