Induced photon emission from quark jets in ultrarelativistic heavy-ion collisions

We study the induced photon bremsstrahlung from a fast quark produced in $AA$-collisions due to multiple scattering in quark-gluon plasma. For RHIC and LHC conditions the induced photon spectrum is sharply peaked at photon energy close to the initial quark energy. In this region the contribution of the induced radiation to the photon fragmentation function exceeds the ordinary vacuum radiation. Contrary to previous analyses [4 – 7] our results show that at RHIC and LHC energies the final-state interaction effects in quark-gluon plasma do not suppress the direct photon production, and even may enhance it at $p_{T}\sim 5$–$15$ GeV.