Charged particle fluctuation as signal of the dynamics in heavy ion processes

We compare the dispersion of the charges in a central rapidity box according to the dual parton model with the predictions of statistical models. Significant deviations are found in heavy ion collisions at RHIC and LHC energies. Hence the charged particle fluctuations should provide a clear signal of the dynamics of heavy ion processes. They should allow one to directly measure the degree of thermalization in a quantitative way. Received: 7 November 2000 / Revised version: 4 September 2001 / Published online: 5 October 2001