PAIR MOMENTUM AND CENTRALITY DEPENDENCES OF 3-D HBT RADII OF CHARGED PIONS MEASURED BY RHIC-PHENIX

We report recent HBT measurements of charged pions in Au+Au and Cu+Cu collisions at by PHENIX at RHIC. The 3-D correlation functions are measured for several centrality and pair momentum regions and 3-D HBT radii are obtained by a traditional Gaussian fit function. By comparing the pion 3-D HBT radii with those measured in Au+Au collisions at , we investigate systematic differences in the 3-D HBT radii as functions of centrality and pair momentum for different collision species and energies.