Abstract
Two-particle momentum correlations between pairs of identical particles produced in relativistic heavyion reactions can be analyzed to extract the information on the spatial and temporal structure of the source as well as the dynamics of fireball in Relativistic Heavy Ion collision.We have calculated twobody correlation function of lepton pairs produced from decay of virtual photon in central Au+Au collisions at the Relativistic Heavy Ion Collider. Our calculation includes contributions from the radiation of lepton pairs from a thermalized QuarkGluonPlasma (QGP) and the subsequent expanding hadron gas. The lepton pair interferometry provides a faithful probe of the details of the spacetime evolution and of the early stages of the system produced in Heavy Ion Collision. We have demonstrated that the study of mass dependence of various HBT radii extracted from the correlation functions of lepton pairs can be used as a powerful tool to characterize and distinguish the hadronic and the partonic phases and also focus on the collective expansion of the system. This study is carried out for Au+Au collisions at √ sNN = 200 GeV by solving relativistic hydrodynamical equations with boost invariance along the longitudinal direction. The equation of state is taken from lattice QCD calculations. The initial conditions for the solution of hydrodynamic equation is constrained by the measured single photon at RHIC. We obtain very different values for the HBT radii (Rside and Rout ) in the mass region around rhomeson and those beyond 1.2 GeV. The physical implications of these results and how these can be used to characterize the hadronic and partonic phases produced in high energy heavyion collisions will be discussed in the presentation
