ORDER-PARAMETER AND SCALING FIELDS IN SELF-ORGANIZED CRITICALITY

We present a unified dynamical mean-held theory for stochastic self-or ganized critical models. We, use a single site approximation, and we i nclude the details of different models by using effective parameters a nd constraints. We identify the order parameter and the relevant scali ng fields in order to describe the critical behavior in terms of the u sual concepts of nonequilibrium lattice models with steady states. We point out the inconsistencies of previous mean-field approaches, which lead to different predictions. Numerical simulations confirm the vali dity of our results beyond mean-field theory.