Higgs scalars and vacuum instability in SU(2)/sub L/ x SU(2)/sub R/ x U(1)

The SU(2)/sub L/ x SU(2)/sub R/ x U(1) model of weak and electromagnetic interactions requires a minimum of two Higgs multiplets, Phi and P, to have the residual electromagnetic U(1) symmetry after the spontaneous symmetry breaking. With this minimum number of Higgs multiplets, we study the existence of a metastable vacuum and the corresponding limits on the masses of Higgs bosons using the effective potential in the one-loop approximation. Demanding that this model have the same neutrino neutral-current interactions as those of th Weinberg-Salam model and using the available phenomenological information, we get the minimum value for the sum of the squares of masses, M/sub plus-or-minus/, of two of the neutral Higgs bosons in terms of a parameter which involves the mixing of Phi and P, assuming a stable asymmetric vacuum exists. Under the assumption that the (mass)2 matrix of the Higgs bosons is diagonal, we obtain (M/sub +/2 + M/sub -/2)/sup 1/2/ > 11.4 GeV. No limit can be placed on the other Higgs bosons with the presently available information