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dc.contributor.authorBaksay, Gyöngyi
dc.contributor.authorBaksay, László A
dc.contributor.authorHohlmann, Marcus
dc.contributor.authorRembeczki, Szabolcs
dc.contributor.authorDehmelt, Klaus
dc.contributor.authorAdare, Andrew Marshall
dc.contributor.authorAfanasiev, Sergei V.
dc.contributor.authorAidala, Christine A.
dc.contributor.authorAjitanand, N. N.
dc.contributor.authorAkiba, Yasuyuki
dc.date.accessioned2015-04-06T19:15:43Z
dc.date.available2015-04-06T19:15:43Z
dc.date.issued2010-03-29
dc.identifier.citationAdare, A., Afanasiev, S., Aidala, C., Ajitanand, N. N., Akiba, Y., Al-Bataineh, H., . . . Zolin, L. (2010). Detailed measurement of the e+e- pair continuum in p+p and Au+Au collisions at √sNN=200 GeV and implications for direct photon production. Physical Review C - Nuclear Physics, 81(3).en_US
dc.identifier.urihttp://hdl.handle.net/11141/528
dc.description.abstractPHENIX has measured the e+e- pair continuum in √sNN=200□ GeV Au+Au and p+p collisions over a wide range of mass and transverse momenta. The e+e- yield is compared to the expectations from hadronic sources, based on PHENIX measurements. In the intermediate-mass region, between the masses of the φ and the J/ψ meson, the yield is consistent with expectations from correlated cc□ production, although other mechanisms are not ruled out. In the low-mass region, below the φ, the p+p inclusive mass spectrum is well described by known contributions from light meson decays. In contrast, the Au+Au minimum bias inclusive mass spectrum in this region shows an enhancement by a factor of 4.7±0. 4stat±1.5syst±0.9model. At low mass (mee<0.3□ GeV/c2) and high pT (1<pT<5□ GeV/c) an enhanced e+e- pair yield is observed that is consistent with production of virtual direct photons. This excess is used to infer the yield of real direct photons. In central Au+Au collisions, the excess of the direct photon yield over the p+p is exponential in pT, with inverse slope T=221±19stat±19syst□ MeV. Hydrodynamical models with initial temperatures ranging from Tinit□□300-600□ MeV at times of 0.6-0.15 fm/c after the collision are in qualitative agreement with the direct photon data in Au+Au. For low pT<1□ GeV/c the low-mass region shows a further significant enhancement that increases with centrality and has an inverse slope of T□□100□ MeV. Theoretical models underpredict the low-mass, low-pT enhancement.en_US
dc.language.isoen_USen_US
dc.rightsThis published article is available in accordance with the publisher's policy. It may be subject to U.S. Copyright Law.en_US
dc.rights.urihttp://journals.aps.org/authors/transfer-of-copyright-agreementen_US
dc.titleDetailed measurement of the e+e- pair continuum in p+p and Au+Au collisions at √sNN=200 GeV and implications for direct photon productionen_US
dc.typeArticleen_US
dc.identifier.doi10.1103/PhysRevC.81.034911


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