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

Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F19%3A10398433" target="_blank" >RIV/00216208:11320/19:10398433 - isvavai.cz</a>
Alternative codes found
RIV/68407700:21340/19:00334194
Result on the web
<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=U1T1LGZin6" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=U1T1LGZin6</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1103/PhysRevLett.123.022301" target="_blank" >10.1103/PhysRevLett.123.022301</a>

Result language
angličtina
Original language name
Beam Energy and Centrality Dependence of Direct-Photon Emission from Ultrarelativistic Heavy-Ion Collisions
Original language description
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.
Czech name
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Czech description
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Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10303 - Particles and field physics

Project
Result was created during the realization of more than one project. More information in the Projects tab.
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year
2019
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

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