Left-right symmetric gauge model with new h−ξR interactions

The Yang-Mills-Higgs Lagrangian of the left-right symmetric gauge model with the symmetry of SU(3)c×SU(2)L×SU(2)R×U(1) is presented by considering the new interaction terms between SU(2)L bidoublet Higgs boson h and SU(2)R adjoint Higgs boson ξR. We also present a parametrization of the Higgs potential and interacting terms in such a way that not only does the cosmological constant vanishes at the tree level but also the light Higgs field emerges without fine tuning of parameters. ξR is responsible for the spontaneous breakdown of SU(2)R×U(1) down to U(1)Y and the seesaw mechanism of neutrino mass is well explained owing to this symmetry breakdown. The Higgs boson h yields the spontaneous breakdown of SU(2)L×U(1)Y down to U(1)em. Due to this new interaction term together with other interaction and potential terms of the Higgs bosons, only one CP-even scalar boson among the bidoublet boson h survives in the weak energy scale and other four scalar bosons acquire the mass of the SU(2)R×U(1) breaking scale, which leads to the same situation as in the standard model.