Measurement of event-by-event fluctuations and order parameters in PHENIX

We present the latest results on event-by-event fluctuations of charged particle multiplicity in Au+Au and Cu+Cu collisions at and 62.4 GeV measured by PHENIX experiment at RHIC. The two particle correlation length to discuss order parameters, which can be extracted from scale dependence of the fluctuations, is supposed to be sensitive to the critical points of QCD phase transition. The obtained correlation length with respect to the pseudo rapidity gap indicates the power law behavior as a function of the number of participant nucleons for Au+Au collisions at .