Geometrical scaling of prompt photons in heavy ion collisions
M. Smoluchowski Institute of Physics, Jagiellonian University, S. Łojasiewicza 11, 30-348 Kraków, Poland
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Published online: 19 April 2019
We discuss geometrical scaling (GS) for the prompt (direct) photons produced in heavy ion collisions. To this end we first introduce the concept of GS and illustrate its emergence on the example of charged particles. Next, we analyse direct photon data from RHIC and from the LHC. We show that thedata supportthehypothesisofGSin termsof participant number relatedto diﬀerent centrality classes. We also study GS at diﬀerent energies, however a more detailed study will be possible only when data for at least three diﬀerent energies from one experiment will be available and also when we use the data obtained from the collisions of large systems (Cu+Cu, Au+Au, Pb+Pb) and small systems (p+p,d+Au,p+Au).
© The Authors, published by EDP Sciences, 2019
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