On the problem of mean time delays in nuclear reactions and peculiarities of the correlation analysis of excitation functions

The identity of two different definitions for time delay in compound nuclear reactions is proved for two approaches basing on examination of the motion of wave packets and on the time-energy Fourier transformation, when the same statistical model is used. It is shown also that if we exclude limitations of Ericson's statistical model, the autocorrelation analysis of fluctuating excitation functions enables to determine parameters of the probability distribution function for time delay in compound nuclear reactions such as the variance, excess coefficient, etc. As an illustrative example, the autocorrelation function for the cross section of the 25 Mg(3He,p) reaction is discussed