Beam Energy and Centrality Dependence of Direct-Photon Emission from Ultrarelativistic Heavy-Ion Collisions

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dc.contributor University of Helsinki, Helsinki Institute of Physics en
dc.contributor University of Helsinki, Helsinki Institute of Physics en
dc.contributor University of Helsinki, Helsinki Institute of Physics en
dc.contributor University of Helsinki, Helsinki Institute of Physics en
dc.contributor.author PHENIX Collaboration
dc.contributor.author Adare, A.
dc.contributor.author Kim, D. J.
dc.contributor.author Krizek, F.
dc.contributor.author Novitzky, N.
dc.contributor.author Rak, J.
dc.date.accessioned 2020-02-25T09:54:01Z
dc.date.available 2020-02-25T09:54:01Z
dc.date.issued 2019-07-10
dc.identifier.citation PHENIX Collaboration , Adare , A , Kim , D J , Krizek , F , Novitzky , N & Rak , J 2019 , ' Beam Energy and Centrality Dependence of Direct-Photon Emission from Ultrarelativistic Heavy-Ion Collisions ' , Physical Review Letters , vol. 123 , no. 2 , 022301 . https://doi.org/10.1103/PhysRevLett.123.022301 en
dc.identifier.issn 0031-9007
dc.identifier.other PURE: 132655891
dc.identifier.other PURE UUID: 3603a589-3113-4a22-813c-faff2300f4f2
dc.identifier.other WOS: 000474895000007
dc.identifier.uri http://hdl.handle.net/10138/312210
dc.description.abstract The PHENIX collaboration presents first measurements of low-momentum (0.4 <p(T) <3 GeV/c) direct-photon yields from Au + Au collisions at root s(NN) =39 and 62.4 GeV. For both beam energies the direct-photon yields are substantially enhanced with respect to expectations from prompt processes, similar to the yields observed in Au +horn Au collisions at root s(NN) =200. Analyzing the photon yield as a function of the experimental observable dN(ch)/d(eta) eveals that the low-momentum (> 1 GeV= c) direct-photon yield dN(gamma)(dir)/d(eta) is a smooth function f dN(ch)/d eta and can be well described as proportional to (dN(ch)/d(eta))(alpha) with a approximate to 1.25. This scaling behavior holds for a wide range of beam energies at the Relativistic Heavy Ion Collider and the Large Hadron Collider, for centrality selected samples, as well as for different A thorn A collision systems. At a given beam energy, the scaling also holds for high p(T) (> 5 GeV= c), but when results from different collision energies are compared, an additional root s(NN) -dependent multiplicative factor is needed to describe the integrated-direct-photon yield. en
dc.format.extent 10
dc.language.iso eng
dc.relation.ispartof Physical Review Letters
dc.rights en
dc.subject DILEPTONS en
dc.subject 114 Physical sciences en
dc.title Beam Energy and Centrality Dependence of Direct-Photon Emission from Ultrarelativistic Heavy-Ion Collisions en
dc.type Article
dc.description.version Peer reviewed
dc.identifier.doi https://doi.org/10.1103/PhysRevLett.123.022301
dc.type.uri info:eu-repo/semantics/other
dc.type.uri info:eu-repo/semantics/publishedVersion
dc.contributor.pbl

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