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Dielectron production in Au plus Au collisions at root s(NN)=200 GeV

Title
Dielectron production in Au plus Au collisions at root s(NN)=200 GeV
Author
김용균
Keywords
SUPER-PROTON SYNCHROTRON; HADRON BLIND DETECTOR; LOW-MASS DILEPTONS; PHENIX EXPERIMENT; CHIRAL RESTORATION; CERN-SPS; CONSTRUCTION; PERFORMANCE; PAIRS
Issue Date
2016-01
Publisher
AMER PHYSICAL SOC
Citation
PHYSICAL REVIEW C, v. 93, NO 1, Article number 014904, Page. 1-34
Abstract
We present measurements of e(+)e-production at midrapidity in Au + Au collisions at root s(NN) = 200 GeV. The invariant yield is studied within the PHENIX detector acceptance over a wide range of mass (m(ee) ˂ 5 GeV/c(2)) and pair transverse momentum (p(T) ˂ 5 GeV/c) for minimum bias and for five centrality classes. The e(+)e(-) yield is compared to the expectations from known sources. In the low-mass region (m(ee) = 0.30-0.76 GeV/c(2)) there is an enhancement that increases with centrality and is distributed over the entire pair p(T) range measured. It is significantly smaller than previously reported by the PHENIX experiment and amounts to 2.3 +/- 0.4(stat) +/- 0.4(syst) +/- 0.2(model) or to 1.7 +/- 0.3(stat) +/- 0.3(syst) +/- 0.2(model) for minimum bias collisions when the open heavy-flavor contribution is calculated with PYTHIA or MC@NLO, respectively. The inclusive mass and p(T) distributions, as well as the centrality dependence, are well reproduced by model calculations where the enhancement mainly originates from the melting of the rho meson resonance as the system approaches chiral symmetry restoration. In the intermediate-mass region (m(ee) = 1.2-2.8 GeV/c(2)), the data hint at a significant contribution in addition to the yield from the semileptonic decays of heavy-flavor mesons.
URI
https://journals.aps.org/prc/abstract/10.1103/PhysRevC.93.014904http://hdl.handle.net/20.500.11754/30568
ISSN
2469-9985; 2469-9993
DOI
10.1103/PhysRevC.93.014904
Appears in Collections:
COLLEGE OF ENGINEERING[S](공과대학) > NUCLEAR ENGINEERING(원자력공학과) > Articles
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