Publication: Beam Energy and Centrality Dependence of Direct-Photon Emission from Ultrarelativistic Heavy-Ion Collisions
Дата
2019
Авторы
Adare, A.
Afanasiev, S.
Aidala, C.
Ajitanand, N. N.
Riabov, V.
Samsonov, V.
Taranenko, A.
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Аннотация
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.
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Beam Energy and Centrality Dependence of Direct-Photon Emission from Ultrarelativistic Heavy-Ion Collisions / Adare, A [et al.] // Physical Review Letters. - 2019. - 123. - № 2. - 10.1103/PhysRevLett.123.022301
URI
https://www.doi.org/10.1103/PhysRevLett.123.022301
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http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=Alerting&SrcApp=Alerting&DestApp=WOS_CPL&DestLinkType=FullRecord&UT=WOS:000474895000007
https://openrepository.mephi.ru/handle/123456789/18373