  In this article we propose standard model strictly forbidden decay modes,
quarkonia (QQ(1^{--}) = J/psi, Upsilon) decays into two photons, as a possible
signature of the space-time non-commutativity. An experimental discovery of
J/psi -> gamma gamma and/or Upsilon -> gamma gamma processes would certainly
indicate a violation of the Landau-Pomeranchuk-Yang theorem and a definitive
appearance of new physics.
