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

Adare, A; Aidala, C.; Ajitanand, N N; Akiba, Y.; Akimoto, R.; Alexander, J J; Alfred, M.; Al-Ta'ani, H.; Angerami, A and Aoki, K., et al. (2016) In Physical Review C (Nuclear Physics) 93(1).
Abstract

We present measurements of e+e- production at midrapidity in Au+Au collisions at sNN=200 GeV. The invariant yield is studied within the PHENIX detector acceptance over a wide range of mass (mee<5 GeV/c2) and pair transverse momentum (pT<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 (mee=0.30-0.76 GeV/c2) there is an enhancement that increases with centrality and is distributed over the entire pair pT 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... (More)

We present measurements of e+e- production at midrapidity in Au+Au collisions at sNN=200 GeV. The invariant yield is studied within the PHENIX detector acceptance over a wide range of mass (mee<5 GeV/c2) and pair transverse momentum (pT<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 (mee=0.30-0.76 GeV/c2) there is an enhancement that increases with centrality and is distributed over the entire pair pT 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 pT distributions, as well as the centrality dependence, are well reproduced by model calculations where the enhancement mainly originates from the melting of the ρ meson resonance as the system approaches chiral symmetry restoration. In the intermediate-mass region (mee=1.2-2.8 GeV/c2), the data hint at a significant contribution in addition to the yield from the semileptonic decays of heavy-flavor mesons.

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Physical Review C (Nuclear Physics)
volume
93
issue
1
publisher
American Physical Society
external identifiers
  • wos:000367895300007
  • scopus:85019287872
ISSN
0556-2813
DOI
10.1103/PhysRevC.93.014904
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English
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089f4b84-1872-438f-b499-006fa856a717 (old id 8745011)
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2016-02-29 09:18:46
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@article{089f4b84-1872-438f-b499-006fa856a717,
  abstract     = {<p>We present measurements of e+e- production at midrapidity in Au+Au collisions at sNN=200 GeV. The invariant yield is studied within the PHENIX detector acceptance over a wide range of mass (mee&lt;5 GeV/c2) and pair transverse momentum (pT&lt;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 (mee=0.30-0.76 GeV/c2) there is an enhancement that increases with centrality and is distributed over the entire pair pT 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 pT distributions, as well as the centrality dependence, are well reproduced by model calculations where the enhancement mainly originates from the melting of the ρ meson resonance as the system approaches chiral symmetry restoration. In the intermediate-mass region (mee=1.2-2.8 GeV/c2), the data hint at a significant contribution in addition to the yield from the semileptonic decays of heavy-flavor mesons.</p>},
  articleno    = {014904},
  author       = {Adare, A and Aidala, C. and Ajitanand, N N and Akiba, Y. and Akimoto, R. and Alexander, J J and Alfred, M. and Al-Ta'ani, H. and Angerami, A and Aoki, K. and Apadula, N. and Aramaki, Y and Asano, H. and Aschenauer, E. C. and Atomssa, E T and Averbeck, R and Awes, T. C. and Azmoun, B and Babintsev, V. and Bai, M. and Bandara, N. S. and Bannier, B. and Barish, K N and Bassalleck, B. and Bathe, S and Baublis, V. and Baumgart, S. and Bazilevsky, A. and Beaumier, M. and Beckman, S. and Belmont, R and Berdnikov, A and Berdnikov, Y. and Blau, D. S. and Bok, J S and Boyle, K and Brooks, M L and Bryslawskyj, J. and Buesching, H. and Bumazhnov, V. and Butsyk, S. and Campbell, S and Castera, P. and Christiansen, P. and Gustafsson, H. and Haslum, E. and Oskarsson, A. and Silvermyr, D. and Stenlund, E. and Velkovska, J. and , },
  issn         = {0556-2813},
  language     = {eng},
  month        = {01},
  number       = {1},
  publisher    = {American Physical Society},
  series       = {Physical Review C (Nuclear Physics)},
  title        = {Dielectron production in Au plus Au collisions at root s(NN)=200 GeV},
  url          = {http://dx.doi.org/10.1103/PhysRevC.93.014904},
  volume       = {93},
  year         = {2016},
}