Dielectron Mass Spectra from Au+Au Collisions at √SNN = 200 GeV

Adamczyk, L. and Planinić, Mirko and Poljak, Nikola and Zyzak, M. (STAR Collaboration) (2014) Dielectron Mass Spectra from Au+Au Collisions at √SNN = 200 GeV. Physical Review Letters, 113 (2). pp. 22301-7. ISSN 0031-9007

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Abstract

We report the STAR measurements of dielectron (e+e−) production at midrapidity (|yee|<1) in Au+Au collisions at √sNN=200  GeV. The measurements are evaluated in different invariant mass regions with a focus on 0.30–0.76 (ρ-like), 0.76–0.80 (ω-like), and 0.98–1.05 (ϕ-like)   GeV/c2. The spectrum in the ω-like and ϕ-like regions can be well described by the hadronic cocktail simulation. In the ρ-like region, however, the vacuum ρ spectral function cannot describe the shape of the dielectron excess. In this range, an enhancement of 1.77±0.11(stat)±0.24(syst)±0.33(cocktail) is determined with respect to the hadronic cocktail simulation that excludes the ρ meson. The excess yield in the ρ-like region increases with the number of collision participants faster than the ω and ϕ yields. Theoretical models with broadened ρ contributions through interactions with constituents in the hot QCD medium provide a consistent description of the dilepton mass spectra for the measurement presented here and the earlier data at the Super Proton Synchrotron energies.

Item Type: Article
Date: July 2014
Subjects: NATURAL SCIENCES > Physics
Additional Information: Copyright (2014) by the American Physical Society.
Divisions: Faculty of Science > Department of Physics
Publisher: American Physical Society
Depositing User: mag. bibl. Marija Turković
Date Deposited: 15 Sep 2014 12:07
Last Modified: 17 Sep 2014 12:54
URI: http://digre.pmf.unizg.hr/id/eprint/2768

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