Hydrodynamic source with continuous emission in Au+Au collisions ats=200GeV

Abstract

We analyze single particle momentum spectra and interferometry radii in central Au+Au collisions at RHIC within a hydro-inspired parametrization accounting for continuous hadron emission through the whole lifetime of hydrodynamically expanding fireball. We found that a satisfactory description of the data is achieved for a physically reasonable set of parameters when the emission from non space-like sectors of the enclosed freeze-out hypersurface is fairly long: 9 fm/c. This protracted surface emission is compensated in outward interferometry radii by positive r out − t correlations that are the result of an intensive transverse expansion. The main features of the experimental data are reproduced: in particular, the obtained ratio of the outward to sideward interferometry radii is less than unity and decreases with increasing transverse momenta of pion pairs. The extracted value of the temperature of emission from the surface of hydrodynamic tube approximately coincides with one found at chemical freeze-out in RHIC Au+Au collisions. A significant contribution of the surface emission to the spectra and to the correlation functions at relatively large transverse momenta should be taken into account in advanced hydrodynamic models of ultrarelativistic nucleus-nucleus collisions.

Bose-Einstein correlations ofπ−π−pairs in central Pb+Pb collisions at20A,30A

“…For instance in Ref. [31] a protracted surface emission is introduced instead of the conventional Cooper-Frye prescription [69]. In this case the k t dependence of the ratio R out /R side is well reproduced.…”

“…The exception remains the overprediction of the experimentally determined pion source radii by several Fermi. This could be due to a too-simplistic treatment of the freeze-out stage [31] and/or a neglect of possible refractive effects in the fireball within the traditional interpretation of BE correlations [32][33][34].…”

Fast hadron freeze-out generator. II. Noncentral collisions

“…The low temperature regime seems to be preferable because the strong transverse flow is expected to describe the large inverse slopes of transverse spectra of the heavy hadrons (especially protons) and small correlation radii obtained at RHIC better [3,11]. We present the calculated correlation radii in section III E.…”

“…The RHIC experimental data are compared with our MC generation results obtained within this thermal freeze-out scenario. We do not consider here a more complex freeze-out scenario taking into account continuous particle emission (see, e.g., [3]). …”

“…Successful attempts to describe simultaneously the momentum-space measurements and the freeze-out coordinate-space data were done in several models which make experimental data fitting within some parametrizations of freeze-out hypersurface: "Kiev-Nantes" model [3], "Blast-Wave" parametrizations [11,12,13], "Buda-Lund" hydro approach [14].…”