Ericson fluctuations for the finite spin relaxation times

Abstract We present the model for preequilibrium statistical (〈 S ( E )〉 E = 0) reactions where the S -matrix elements with different spin-values are correlated. In this model time-delayed differential cross-sections have the form of classical diffusion processes in time-scattering-angle space. As a consequence the energy autocorrelation function of fluctuating cross-sections does not have Lorentzian angle-independent shape but takes negative values and displays oscillating behaviour. We present a comparison with data showing such oscillations.