Modified renormalization strategy for sandpile models

Following the renormalization-group scheme recently developed by Pietronero et al. [Phys. Rev. Lett. 72, 1690 (1994)] we introduce a simplifying strat egy for the renormalization of the relaxation dynamics of sandpile models. In our scheme, five subcells at a generic scale b form the renormalized cel l at the next larger scale. Now the fixed point has a unique nonzero dynami cal component that allows for a great simplification in the computation of the critical exponent z. The values obtained are in goad agreement with bot h numerical and theoretical results previously reported. [S1063-651X(99)061 12-7].