The quantum vacuum of the minimal SO(10) GUT

We reexamine the longstanding no-go excluding all potentially viable SO(10) → SU(3)cx SU(2)L x U(1)Y symmetry breaking patterns within the minimal renormalizable non-supersymmetric SO(10) GUT framework featuring the 45-dimensional adjoint representation in the Higgs sector. A simple symmetry argument indicates that quantum effects do change the vacuum structure of the model dramatically. A thorough analysis of the one-loop effective potential reveals that the phenomenologically favoured symmetry breaking chains passing through the SU(4)C x SU(2)L x U(1)R or SU(3)c x SU(2)L x SU(2)R x U(1)B-L intermediate stages are, indeed, supported at the quantum level. This brings the class of minimal non-supersymmetric SO(10) GUTs back from oblivion, providing a new ground for a potentially realistic model building.