Physics and Astronomy
Journal or Book Title
Physical Review Letters
Neutral pion transverse momentum (p(T)) spectra at midrapidity (|y| less than or similar to 0.35) were measured in Cu + Cu collisions at root s(NN) = 22.4, 62.4, and 200 GeV. Relative to pi(0) yields in p + p collisions scaled by the number of inelastic nucleon-nucleon collisions (N-coll) the pi(0) yields for p(T) greater than or similar to 2 GeV/c in central Cu + Cu collisions are suppressed at 62.4 and 200 GeV whereas an enhancement is observed at 22.4 GeV. A comparison with a jet-quenching model suggests that final state parton energy loss dominates in central Cu + Cu collisions at 62.4 and 200 GeV, while the enhancement at 22.4 GeV is consistent with nuclear modifications in the initial state alone.
American Physical Society
Adare, Andrew; Grau, Nathan C.; Hill, John C.; Kempel, Todd; Lajoie, John G.; Lebedev, Alexandre; Ogilvie, Craig; Pei, H.; Rosati, Marzia; Semenov, Alexey Yu.; Skutnik, S.; Vale, Carla; Wei, Feng; et al.; and PHENIX Collaboration, "Onset of pi(0) Suppression Studied in Cu plus Cu Collisions at root s(NN)=22.4, 62.4, and 200 GeV" (2008). Physics and Astronomy Publications. 303.