Production of Light Neutral Mesons in Ultrarelativistic Cu + Au and U + U Collisions in the Region of Mean Velocities

Abstract

Results are presented from measuring nuclear modification factors R_AA of the π⁰, η, K_S, and ω mesons produced in systems of Cu + Au and U + U collisions at cms energies of $\sqrt {{{s}_{{NN}}}}$ = 200 and 192 GeV, respectively, in the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC). The R_AA values are found not to depend on the type of neutral meson and to vary in the ~0.4–0.6 and ~0.2–0.3 intervals for central Cu + Au and U + U collisions, respectively. The mean R_AA values for different collision systems (Au + Au, Cu + Cu, Cu + Au, and U + U) are found to coincide within the measuring errors when estimated at comparable values of collision energy $\sqrt {{{s}_{{NN}}}}$, and of the number of nucleons participating in a nucleus–nucleus collision, N_part.