  We study collider implications of variant axion models which naturally avoid
the cosmological domain wall problem. We find that in such models the branching
ratio of $h \to \gamma\gamma$ can be enhanced by a factor of 5 up to 30 as
compared with the standard model prediction. The $h \to \gamma\gamma$ process
is therefore a promising channel to discover a light Higgs boson at the LHC and
to probe the Peccei-Quinn charge assignment of the standard model fields from
Yukawa interactions.
