Physical Review C
Measurements of the anisotropy parameter v₂ of identified hadrons (pions, kaons, and protons) as a function of centrality, transverse momentum pT, and transverse kinetic energy KET at midrapidity (|η|<0.35) in Au+Au collisions at √sNN=200 GeV are presented. Pions and protons are identified up to pT= 6 GeV/c, and kaons up to pT= 4 GeV/c, by combining information from time-of-flight and aerogel Čerenkov detectors in the PHENIX Experiment. The scaling of v₂ with the number of valence quarks (nq) has been studied in different centrality bins as a function of transverse momentum and transverse kinetic energy. A deviation from previously observed quark-number scaling is observed at large values of KET/nq in noncentral Au+Au collisions (20-60%), but this scaling remains valid in central collisions (0-10%).
Adare, Andrew Marshall; Baksay, Gyöngyi; Baksay, László A.; Hohlmann, Marcus; and PHENIX Collaboration, "Deviation From Quark Number Scaling Of The Anisotropy Parameter v₂ Of Pions, Kaons, And Protons In Au+Au Collisions At √s NN=200 GeV" (2012). Aerospace, Physics, and Space Science Faculty Publications. 449.