  PHENIX has measured high transverse momentum (pT) identified hadrons in
different collision species and energies in the last five RHIC runs. The
systematic study of the high pT hadron production provides an idea on
interaction of hard scattered partons and the matter created in relativistic
heavy ion collision. The eta/pi0 ratio is measured in Au+Au collisions, which
gives a hint on the system thermalization and particle production. A future
measurement of hadron and photon measurement is discussed.
