Quantum dynamics, the RHIC HBT puzzle, and the chiral phase transition

Abstract

We use a relativistic optical model formalism to describe the emission of pions produced within a dense, strongly-interacting system of matter in the presence of strong radial flow and absorption. The attenuated or unattenuated plane waves of earlier emission function approaches are replaced with “distorted wave” solutions to a relativistic wave equation including a complex optical potential. The resulting distorted-wave emission function model (DWEF) is used in numerical calculations to describe HBT correlations and the resonance-corrected pion spectrum from central-collision STAR Au+Au pion data at s = 200 GeV . The parameters of the emission function are constrained by adopting a pion formation temperature taken from lattice gauge calculations and a chemical potential equal to the pion mass suggested by chiral symmetry restoration. The optical has strong attraction as well as absorption. Excellent agreement with the STAR data are obtained. The applications are extended by applying linear participant scaling to the space-time parameters of the model, so that we predict HBT radii over a range of centralities for both Au+Au and Cu+Cu collisions. Good agreement is found with STAR HBT data for all but the most peripheral collisions. For outgoing pion momenta less than about 500 MeV/c, our pionic distorted wave functions are very different than the corresponding functions obtained by using the familiar eikonal approximation. All of the results presented in the talk are in Refs. [J.G. Cramer, G.A. Miller, J.M.S. Wu and J.H.S. Yoon, Phys. Rev. Lett. 94 (2005) 102302 arXiv:nucl-th/0411031 ], [G.A. Miller and J.G. Cramer, Polishing the lens. I: Pionic final state interactions and HBT correlations. Distorted wave emission function (DWEF) formalism and examples, arXiv:nucl-th/0507004 , submitted to Phys. Rev. C].