Nonequilibrium Photons as a Signature of Quark-hadron Phase Transition
  We study the nonequilibrium photon production in the quark-hadron phase transition, using the Friedberg-Lee type solitons as a working model for quark-hadron physics. We propose that to search for nonequilibrium photons in the direct photon measurements of heavy-ion collisions may be a characteristic test of the transition from the quark-gluon to hadronic phases. 
Da-Shin Lee (Dong Hwa Univ.) and Kin-Wang Ng (Inst. of Physics,   Academia Sinica, Taiwan)