Fidelity of photon interferometry for recording the evolution of a nascent quark-gluon plasma

The fidelity of two-photon intensity interferometry for reflecting the dynamics of a nascent quark-gluon plasma formed in a high energy nucleus-nucleus collision is examined. A (3+1)-dimensional expansion of the plasma as well as a (1+1)-dimensional expansion according to Bjorken hydrodynamics, both with a first order phase transition, are considered. The correlation of high transverse-momentum photons is shown to be a precision tool for the investigation of the space-time evolution of the high-density QCD plasma. In particular, the longitudinal correlation function, which depicts the time development of the system, is seen to have its origin in two sources: one corresponding to the early plasma phase and the second to the later stages. This aspect may help identify thermal photons according to their ''time of birth'' during evolution