Physics and Astronomy
Journal or Book Title
Physical Review C
Direct photons have been measured in root s(NN) = 200 GeV d + Au collisions at midrapidity. A wide p(T) range is covered by measurements of nearly real virtual photons (1 < p(T) < 6 GeV/c) and real photons (5 < p(T) < 16 GeV/c). The invariant yield of the direct photons in d + Au collisions over the scaled p + p cross section is consistent with unity. Theoretical calculations assuming standard cold-nuclear-matter effects describe the data well for the entire p(T) range. This indicates that the large enhancement of direct photons observed in Au + Au collisions for 1.0 < p(T) < 2.5 GeV/c is attributable to a source other than the initial-state nuclear effects.
American Physical Society
Adare, Andrew; Belikov, Sergey; Constantin, Paul; Dion, Alan; Grau, Nathan C.; Hill, John C.; Kempel, Todd; Lajoie, John G.; Lebedev, Alexandre; Ogilvie, Craig; Pei, H.; Rak, Jan; Rosati, Marzia; Semenov, Alexey Yu.; Silva, C. L.; Vale, Carla; Wei, Feng; Wohn, F. K.; Zong, X.; et al.; and PHENIX Collaboration, "Direct photon production in d+Au collisions at root s(NN)=200 GeV" (2013). Physics and Astronomy Publications. 269.