arXiv subjects

A. Ster

Publications and source records attributed to A. Ster.

27 records · Page 2Linked to original sources

arXiv2004

Indication of quark deconfinement and evidence for a Hubble flow in 130 and 200 GeV Au+Au collisions

Buda-Lund hydro model fits are compared to BRAHMS, PHENIX, PHOBOS and STAR data on identified particle spectra, two-particle Bose-Einstein or HBT correlations, charged particle pseudorapidity distributions and pseudorapidity as well as p_t dependent elliptic flow in sqrt(s_NN) = 130 and 200 GeV Au+Au collisions at RHIC. Preliminary results indicate that 7/8-th of the particle emitting volume is rather cold, with surface temperature of 105 MeV, but the temperature has a distribution and the most central 1/8-th of the volume is superheated to temperatures above the critical value, T(x) > T_c = 172 \pm 3 MeV.

nucl-th↗

arXiv2004

A hint at quark deconfinement in 200 GeV Au+Au data at RHIC

We give the emission function of the axially symmetric Buda-Lund hydro model and present its simultaneous, high quality fits to identified particle spectra, two-particle Bose-Einstein or HBT correlations and charged particle pseudorapidity distributions as measured by BRAHMS and PHENIX in 0-30 % central, $\sqrt{s_{\NN}} = 200$ GeV Au+Au collisions at RHIC. The best fit is achieved when the most central region of the particle emitting volume is superheated to $T_0 = 200 \pm 9$ MeV $ \ge T_c =172 \pm 3$ MeV, a preliminary, 3 $σ$ effect.

nucl-th↗

arXiv2003

An indication for deconfinement in Au+Au collisions at RHIC

We present simultaneous, quality fits to final BRAHMS, PHENIX, PHOBOS and STAR data on particle spectra and two-particle Bose-Einstein or HBT correlations as measured in Au+Au collisions at $\sqrt{s_{NN}} = 130$ GeV. Using the Buda-Lund hydro model, the best fit is achieved when the most central 1/8th of the particle emitting volume is superheated to $T > T_c =170$ MeV. In contrast, we find no indication for such a hot central region in a similar analysis of Pb+Pb data at CERN SPS.

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arXiv2002

The reconstructed final state of Au + Au collisions from PHENIX and STAR data at sqrt{s}=130 AGeV - indication for quark deconfinement at RHIC

The final state of Au + Au collisions at sqrt{s}=130 AGeV at RHIC has been reconstructed within the framework of the Buda-Lund hydrodynamical model, by performing a simultaneous fit to final data on two-particle Bose-Einstein correlations of the STAR and PHENIX Collaborations, and final identified single particle spectra as measured by the PHENIX Collaboration. The results indicate a strongly three-dimensional expansion with a four-velocity field that is almost a spherically symmetric Hubble flow. We find large transverse geometrical source sizes, R_G = 9.8 +- 1.2 fm, a relatively short mean freeze-out time of tau0 = 6.1 +- 0.3 fm/c and a short duration of particle emission, Delta_tau = 0.02 +- 1.5 fm/c. Most strikingly, we find an indication for a hot central part or the hydrodynamically evolving core, characterized by a central temperature of T0 = 202 +- 13 MeV, that is close to (or even above) the deconfinement temperature of the quark-hadron phase transition. The best fit indicates a cold surface temperature of T_s = 110 +- 16 MeV. When the possibility of the hot center is excluded, the confidence level of the fit decreases from 28.9 % to 1.2 %. Predictions are made for the rapidity dependence of the slope parameters, for the transverse mass dependence of the rapidity-width of the single-particle spectra, and for the transverse velocity dependence of the non-indentical particle correlations.

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arXiv2001

The reconstructed Big Bang from RHIC data

The final state of $Au + Au$ collisions at sqrt{s}=130 AGeV at RHIC has been reconstructed within the framework of the Buda-Lund hydro model, by performing a simultaneous fit to preliminary PHENIX and STAR data on two-particle Bose-Einstein correlations and identified single particle spectra. The Hubble constant of the expanding final state of this heavy ion collision is determined to be H = = 0.77 +- 0.09.

hep-ph↗

arXiv2001

Modelling correlations in heavy ion collisions

Modelling correlations in heavy ion collisions is reviewed from model independent characterization of the two-particle correlations to Buda-Lund hydro model fits to correlations and spectra in Au + Au collisions at sqrt{s}=130 AGeV at RHIC.

hep-ph↗

arXiv1999

Partial coherence in the core/halo picture of Bose-Einstein n-particle correlations

We study the influence of a possible coherent component in the boson source on the two-, three- and $n$-particle correlation functions in a generalized core/halo type of boson-emitting source. In particular, a simple formula is presented for the strengh of the $n$-particle correlation functions for such systems. Graph rules are obtained to evaluate the correlation functions of arbitrary high order. The importance of experimental determination of the 4-th and 5-th order Bose-Einstein correlation function is emphasized.

hep-ph↗

arXiv1998

On source parameters from particle correlations and spectra

Analytic and numeric approximations are studied in detail for a hydrodynamic parameterization of single-particle spectra and two-particle correlation functions in high energy hadron-proton and heavy ion reactions. Two very different sets of model parameters are shown to result in similarly shaped correlation functions and single particle spectra in a rather large region of the momentum space. However, the absolute normalization of the single-particle spectra is found to be highly sensitive to the choice of the model parameters. For data fitting the analytic formulas are re-phrased in terms of parameters of direct physical meaning, like mean transverse flow. The difference between the analytic and numeric approximations are determined as an analytic function of source parameters.

hep-ph↗

arXiv1998

Testing Buda-Lund hydro model on particle correlations and spectra in NA44, WA93 and WA98 heavy ion experiments

Analytic and numerical approximations to a hydrodynamical model describing longitudinally expanding, cylindrically symmetric, finite systems are fitted to preliminary NA44 data measured in 200 AGeV central $S + Pb$ reactions. The model describes the measured spectra and HBT radii of pions, kaons and protons, simultaneously. The source is characterized by a central freeze-out temperature of T_0 = 154 +/- 8 +/- 11 MeV, a "surface" temperature of T_r = 107 +/- 28 +/- 18 MeV and by a well-developed transverse flow, = 0.53 +/- 0.17 +/- 0.11. The transverse geometrical radius and the mean freeze-out time are found to be R_G = 5.4 +/- 0.9 +/- 0.7 fm and tau_0 = 5.1 +/- 0.3 +/- 0.3 fm/c, respectively. Fits to preliminary WA93 200 AGeV S + Au and WA98 158 AGeV Pb + Pb data dominated by pions indicate similar model parameters. The absolute normalization of the measured particle spectra together with the experimental determination of both the statistical and the systematic errors were needed to obtain successful fits.

hep-ph↗