Light from Cascading Partons in Relativistic Heavy-Ion Collisions
  We calculate the production of high energy photons from Compton and annihilation processes as well as fragmentation off quarks in the parton cascade model. The multiple scattering of partons is seen to lead to a substantial production of high energy photons, which rises further when parton multiplication due to final state radiation is included. The photon yield is found to be proportional to the number of collisions among the cascading partons. 
Steffen A. Bass, Berndt M\"uller and Dinesh K. Srivastava