The New Extended Left-Right Symmetric Grand Unified Model with SO(3) Family Symmetry

We suggest a new left-right symmetric grand unified model by extending Pati-Salam group to contain an isospin SU(2) and a flavor SO(3) subgroup, where the superheavy fermions are introduced as a mirror to the low-energy standard model fermions. The model undergoes three steps to break to the SM by means of the specified Higgs multiplets. The few parameters can elegantly accommodate whole mass spectra for all the particles at the electroweak scale, especially, two different flavor mixing for the quark and lepton sectors are very well in agreement with the current experimental data. The matter-antimatter asymmetry in the universe is successfully implemented through a new baryogenesis mechanism, in which the B L violating decays of the superheavy gauge boson play a crucial role. The model also predicts that the lightest right-handed Majorana neutrino, whose mass is about several hundred GeVs, is a desired candidate for the cold dark matter. PACS: 12.10.-g; 12.60.-i; 12.15.Ff; 95.35.+d