We propose a new approach to the left-right-symmetric models of weak interactions where parity-and ${\mathrm{SU}\mathrm{}\left(2\right)\mathrm{}}_R$-breaking scales are decoupled from each other. This changes the spectrum of Higgs bosons, which in turn affects the evolution of various gauge coupling constants with energy. This has profound implications for mass hierarchies in partial unification models based on ${\mathrm{SU}\mathrm{}\left(2\right)\mathrm{}}_L\times {\mathrm{SU}\mathrm{}\left(2\right)\mathrm{}}_R\times {\mathrm{SU}\mathrm{}\left(4\right)\mathrm{}}_C$ and grand unified SO(10) models. We find several interesting SO(10)-breaking chains with and without an intermediate ${\mathrm{U}\mathrm{}\left(1\right)\mathrm{}}_R$ symmetry for which both $M_{W_R^{\pm }}$ and $M_{Z_R}$ masses are in the range of 1-20 TeV. We also find a symmetry-breaking pattern for which the ${\mathrm{SU}\mathrm{}\left(4\right)\mathrm{}}_C$-breaking scale is in the range of ${10}^5$ GeV. These patterns lead to observable $\Delta B=2\mathrm{}$ as well as other right-handed-current effects at low energies.

• Received 13 February 1984

DOI:https://doi.org/10.1103/PhysRevD.30.1052