The Renyi entropy H_2 as a rigorous, measurable lower bound for the   entropy of the interaction region in multiparticle production processes
  A model-independent lower bound on the entropy S of the multiparticle system produced in high energy collisions, provided by the Renyi entropy H_2, is shown to be very effective. Estimates show that the ratio H_2/S remains close to one half for all realistic values of the parameters. 
A. Bialas, W. Czyz and K. Zalewski