SU (5) × SU (5) unification model with see-saw mechanism and automatic R-parity conservation

A supersymmetric grand unified model based on the gauge group SU (5) × SU (5) is discussed. This model has the new feature that the conventional see-saw mechanism for neutrino masses is embedded using the (15, 1) + (1, 15) representations. This representation may have a better chance of arising from level two compactification of superstring theories than the 126-dimensional representation used in the SO(10) grand unified models. The model also naturally suppresses all R-parity violating interactions.