Systematic study of identified particle production in PHENIX

Large enhancement of (anti)protons relative to pions has been observed at intermediate in central Au+Au collisions at RHIC. To investigate the possible source of this baryon enhancement, we performed a systematic study of identified hadron spectra in Au+Au and Cu+Cu collisions at , and Au+Au collisions at . The data set allows us to study the energy dependence and system size dependence of the baryon enhancement. We also compare the nuclear modification factors on hadron production in two different collision systems.