Beam-energy-dependent two-pion interferometry and the freeze-out eccentricity of pions measured in heavy ion collisions at the STAR detector

Adamczyk, L. and Planinić, Mirko and Poljak, Nikola and Zyzak, M. (STAR Collaboration) (2015) Beam-energy-dependent two-pion interferometry and the freeze-out eccentricity of pions measured in heavy ion collisions at the STAR detector. Physical Review C, 92 (1). pp. 14904-27. ISSN 0556-2813

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Abstract

We present results of analyses of two-pion interferometry in Au+Au collisions at √sNN=7.7, 11.5, 19.6, 27, 39, 62.4, and 200 GeV measured in the STAR detector as part of the BNL Relativistic Heavy Ion Collider Beam Energy Scan program. The extracted correlation lengths (Hanbury-Brown–Twiss radii) are studied as a function of beam energy, azimuthal angle relative to the reaction plane, centrality, and transverse mass (mT) of the particles. The azimuthal analysis allows extraction of the eccentricity of the entire fireball at kinetic freeze-out. The energy dependence of this observable is expected to be sensitive to changes in the equation of state. A new global fit method is studied as an alternate method to directly measure the parameters in the azimuthal analysis. The eccentricity shows a monotonic decrease with beam energy that is qualitatively consistent with the trend from all model predictions and quantitatively consistent with a hadronic transport model.

Item Type: Article
Date: 10 July 2015
Subjects: NATURAL SCIENCES > Physics > Nuclear Physics
Additional Information: Copyright (2015) by the American Physical Society.
Divisions: Faculty of Science > Department of Physics
Publisher: American Physical Society
Depositing User: Gordana Stubičan Ladešić
Date Deposited: 22 Jul 2015 10:31
Last Modified: 22 Jul 2015 10:32
URI: http://digre.pmf.unizg.hr/id/eprint/4160

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