Ericson fluctuations, detailed balance and time-reversal invariance

Precise detailed balance experiments of fluctuating nuclear reaction cross sections in the Ericson regime provide stringent tests of time reversal invariance in the strong interaction. The interpretation of these experiments requires a statistical theory that describes the interplay of experimental errors and a possible time reversal symmetry breaking amplitude. Such a theory is developed here under the assumption of gaussian probability distributions for both of them. The theory is applied to reanalyze the two detailed balance experiments using the reactions 24Mg+α↔27Al+p at different energies. The theory allows a combined analysis of both experiments. One finds that the relative strength of a possible time reversal symmetry breaking amplitude is ξ<1.25x10-3 with 80% confidence. (orig.)