  Bardeen has argued that once the classically conformal invariance and its
minimal violation by quantum anomalies are imposed on the SM, it can be free
from the quadratic divergences and hence the gauge hierarchy problem. Under the
hypothesis, We investigated the minimal B-L extended SM with a flat Higgs
potential at the Planck scale. In this model, the B-L symmetry is radiatively
broken at TeV scale. We studied phenomenology and detectability of the model at
LHC and the ILC.
