2018/12/24 by V. Khachatryan, Khachatryan, Vladimir
Physics and Astronomy · #FOS: Physical sciences #High-Energy Particle Collisions Research #Nuclear Experiment (nucl-ex) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.1812.09837
openalex publication_date 2018/12/24 · openalex created_date 2022/08/01 · openalex updated_date 2026/07/28
The PHENIX collaboration has measured low momentum direct photon radiation in\nAu+Au collisions at 200 GeV, 62.4 GeV and 39 GeV, in Cu+Cu at 200 GeV as well\nas in p+p, p+Au and d+Au at \√sNN = 200 GeV. In these measurements\nPHENIX has discovered a large excess over the scaled p+p yield of direct\nphotons in A+A collisions, and a non-zero excess, observed within systematic\nuncertainties, over the scaled p+p yield in central p+A collisions. Another\nfinding is that at low-pT the integrated yield of direct photons,\ndN\γ/dy, from large systems shows a behavior of universal scaling as a\nfunction of the charged-particle multiplicity, (dNch/d\η)\α, with\n\α = 1.25, which means that the photon production yield increases faster\nthan the charged-particle multiplicity.\n