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

, ; Adare, A.; Christiansen, Peter LU ; Gustafsson, Hans-Åke LU ; Haslum, Eva LU ; Nystrand, Joakim LU ; Oskarsson, Anders LU ; Otterlund, Ingvar LU ; Rosendahl, Sarah LU and Silvermyr, David LU , et al. (2019) In Physical Review Letters 123(2).
Abstract
The PHENIX collaboration presents first measurements of low-momentum (0.41 GeV/c) direct-photon yield dNγdir/dη is a smooth function of dNch/dη and can be well described as proportional to (dNch/dη)α with α≈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+A collision systems. At a given beam energy, the scaling also holds for high pT (>5 GeV/c), but when results from different collision energies are compared, an additional sNN-dependent multiplicative factor is needed to describe the integrated-direct-photon yield. © 2019 authors. Published by the American Physical Society.
Please use this url to cite or link to this publication:
@article{706ed61f-7215-47b5-849d-9bea331d46c1,
  abstract     = {The PHENIX collaboration presents first measurements of low-momentum (0.41 GeV/c) direct-photon yield dNγdir/dη is a smooth function of dNch/dη and can be well described as proportional to (dNch/dη)α with α≈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+A collision systems. At a given beam energy, the scaling also holds for high pT (>5 GeV/c), but when results from different collision energies are compared, an additional sNN-dependent multiplicative factor is needed to describe the integrated-direct-photon yield. © 2019 authors. Published by the American Physical Society.},
  articleno    = {022301},
  author       = {,  and Adare, A. and Christiansen, Peter and Gustafsson, Hans-Åke and Haslum, Eva and Nystrand, Joakim and Oskarsson, Anders and Otterlund, Ingvar and Rosendahl, Sarah and Silvermyr, David and Stenlund, Evert and Tydesjö, Henrik and Zou, L.},
  issn         = {1079-7114},
  keyword      = {Heavy ions,Photons,Au+Au collisions,Collision energies,Collision systems,Large Hadron Collider,Multiplicative factors,Relativistic Heavy Ion Collider,Scaling behavior,Ultrarelativistic heavy ion collision,Colliding beam accelerators},
  language     = {eng},
  month        = {07},
  number       = {2},
  publisher    = {American Physical Society},
  series       = {Physical Review Letters},
  title        = {Beam Energy and Centrality Dependence of Direct-Photon Emission from Ultrarelativistic Heavy-Ion Collisions},
  url          = {http://dx.doi.org/10.1103/PhysRevLett.123.022301},
  volume       = {123},
  year         = {2019},
}