NUKLEONIKA 2006, 51(Suppl. 3):s55-s58

PRELIMINARY RESULTS ON DIRECT PHOTON-PHOTON MEASUREMENTS IN Ö(sNN) = 62.4 GeV AND 200 GeV Au+Au COLLISIONS AT RHIC

Debasish Das1, Guoji Lin2, Subhasis Chattopadhyay1, Alexei Chikanian2, Evan Finch2, Tapan K. Nayak1, Sergey Y. Panitkin3, Jack Sandweiss2, Alexandre Alarcon Suaide4, Haibin Zhang3
for the STAR Collaboration

1 Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata 700064, India
2 Yale University, Physics Department, P. O. Box 208120, New Haven, Connecticut 06520, USA
3 Physics Department, Brookhaven National Laboratory, P. O. Box 5000, Upton, NY 11973, USA
4 Instituto de Fisica da Universidade de São Paulo, P. O. Box 66318, São Paulo 05314-970, Brazil

We present the preliminary results on direct photon interferometry measurements in Au+Au collisions at Ö(sNN) = 62.4 GeV 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 with 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.