Tests of Time-Reversal Symmetry in Compound-Nucleus Reactions

Abstract
Using a generating function with both commuting and anticommuting variables, we calculate perturbatively the violation of the principle of detailed balance due to breaking of time-reversal symmetry in a statistical nuclear reaction. We apply this result to the best data and establish upper bounds for the strength of, and the spreading width associated with, the symmetry-breaking part of the Hamiltonian. We argue that the spreading width is the fundamental parameter of the theory. A way of further improving the upper bounds is suggested.