A. Adare, University of Colorado, Boulder
Nicole J. Apadula, Iowa State University and Stony Brook University
Sergey Belikov, Iowa State University and Brookhaven National Laboratory
Paul Constantin, Iowa State University and Los Alamos National Laboratory
Lei Ding, Iowa State University
Alan Dion, Iowa State University and Stony Brook University
Nathan C. Grau, Iowa State University, Augustana University, and Columbia University
John C. Hill, Iowa State University
Nels J. Hotvedt, Iowa State University
Todd Kempel, Iowa State University
John G. Lajoie, Iowa State UniversityFollow
Alexandre Lebedev, Iowa State UniversityFollow
S. H. Lee, Iowa State University and Stony Brook University
Craig Ogilvie, Iowa State UniversityFollow
Milap R. Patel, Iowa State UniversityFollow
H. Pei, Iowa State University
Jan Rak, Iowa State University, Helsinki Institute of Physics and University of Jyvaskyla, and University of New Mexico
Timothy T. Rinn, Iowa State University
Marzia Rosati, Iowa State UniversityFollow
Jonathan C. Runchey, Iowa State UniversityFollow
Alexey Yu. Semenov, Iowa State University
Abhisek Sen, Iowa State University and Georgia State University
M. Shimomura, Iowa State University, Nara Women's University, and University of Tsukuba
C. L. Silva, Iowa State University, Los Alamos National Laboratory, and Universidade de Sao Paulo
S. Skutnik, Iowa State University
Carla Vale, Iowa State University and Brookhaven National Laboratory
Feng Wei, Iowa State University and New Mexico State University
et al.
PHENIX Collaboration

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Physics and Astronomy

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The PHENIX collaboration presents first measurements of low-momentum (0.41\,GeV/c) direct-photon yield dNdirγ/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.


This is a pre-print of the article Adare, A., S. Afanasiev, C. Aidala, N.N. Ajitanand, Y. Akiba et al. "Beam-energy and centrality dependence of direct-photon emission from ultra-relativistic heavy-ion collisions." arXiv preprint arXiv:1805.04084v2 (2019). Posted with permission.

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