Surprises from Quarkonium Decay into Photons
  The perturbative QCD approach to quarkonium decay into a photon and hadrons is reconsidered. It is shown that a consistent treatment within perturbative QCD calls for the introduction of a fragmentation contribution which has been neglected so far. The ensuing phenomenological implications are discussed, and, in particular, the possibility of measuring the gluon fragmentation function of the photon is addressed.   *To appear in the proceedings of the workshop QCD94, Montpellier, July '94. 
S. Catani and F. Hautmann