Three-dimensional pion and kaon emission source functions are extracted from hydrokinetic model (HKM) simulations of central Au+Au collisions at the top Relativistic Heavy Ion Collider (RHIC) energy $\sqrt{s_{NN}}=200$ GeV. The model describes well the experimental data, previously obtained by the PHENIX and STAR collaborations using the imaging technique. In particular, the HKM reproduces the non-Gaussian heavy tails of the source function in the pair transverse momentum (out) and beam (long) directions, observed in the pion case and practically absent for kaons. The role of rescatterings and long-lived resonance decays in forming the mentioned long-range tails is investigated. The particle rescattering contribution to the out tail seems to be dominating. The model calculations also show substantial relative emission times between pions (with mean value 13 fm/$c$ in the longitudinally comoving system), including those coming from resonance decays and rescatterings. A prediction is made for the source functions in Large Hadron Collider (LHC) Pb+Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV, which are still not extracted from the measured correlation functions.

• Received 29 August 2013

DOI:https://doi.org/10.1103/PhysRevC.88.064904