Describing transverse dynamics and space-time evolution at RHIC in a hydrodynamic model with statistical hadronization

A hydrodynamic model coupled to the statistical hadronization code Therminator is used to study a set of observables in the soft sector at RHIC. A satisfactory description of the p⊥-spectra and elliptic flow is obtained, similarly to other hydrodynamic models. With the Gaussian initial conditions the transverse femtoscopic radii are also reproduced, providing a possible solution of the RHIC HBT puzzle. 1. Intoduction 1 The consistent description of various features of the soft hadron production in the nucleus2 nucleus collisions at the Relativistic Heavy-Ion Collider (RHIC) is a well known problem [1]. 3 The so called RHIC HBT puzzle [1, 2, 3, 4] refers to the difficulty of simultaneous description 4 of the hadronic transverse-momentum spectra, the elliptic flow coefficient v2, and the Hanbury5 Brown–Twiss (HBT) interferometry data in various approaches including hydrodynamics [5, 6, 6 7, 8, 9]. 7 Recently, we have constructed a hydrodynamic code [10, 11] that is coupled to the statistical hadronization model Therminator [12]. Within this approach a successful uniform description of the soft hadronic RHIC data has been accomplished [13]. The main ingredients of our approach are the following: i) We use a realistic equation of state that interpolates between the lattice QCD results at high temperatures and the hadron-gas results at lower temperatures [14]. ii) The single freeze-out scenario including all well established resonance states is assumed [15]. This assumption leads to shorter emission times and helps to reproduce the ratio Rout/Rside. iii) The use of Therminator allows for the use of two-particle methods in the evaluation of the correlation functions (with and without the Coulomb corrections). iv) The early starting/thermalization time τi = 0.25 fm is assumed. This helps to develop fast the transverse flow and shortens the evolution time. v) The initial conditions for the energy density in the transverse plane are taken in the Gaussian form [13] ε(x⊥) = εi exp (