Preliminary Results on Direct Photon-Photon HBT Measurements in   $\sqrt{s_{\rm{NN}}}$ = 62.4 GeV and 200 GeV Au+Au Collisions at RHIC
  We present the preliminary results on direct photon interferometry measurements in Au+Au collisions at $\sqrt{s_{\rm{NN}}}$ = 62.4 and 200 GeV using the STAR (Solenoidal Tracker at RHIC) detector. Photons are reconstructed via $e^+/e^-$ conversions in STAR Time Projection Chamber(TPC) and energy deposited by photons in STAR Barrel Electromagnetic Calorimeter(BEMC). The two-photon correlations are measured using (1) both photons measured using BEMC; (2) one photon from conversions and the other measured with BEMC. Both the methodologies and the possible constraints in the correlation function measurements are discussed. 
Debasish Das, Guoji Lin, Subhasis Chattopadhyay, Alexei Chikanian,   Evan Finch, Tapan K Nayak, Sergey Y Panitkin, Jack Sand...