Exotic nuclear physics with low-energy neutrons

Snow replies: I also wish that I had been able to say more about the contribution of neutron measurements to the development of statistical treatments of excited nuclear states and the fruitful random matrix theory ideas that came out of them. They have broad applications in many areas of physics, and I thank Harry Camarda for his letter and references describing that physics.

Camarda’s letter also provides the opportunity to highlight a fascinating subsequent development in the field—namely, the amplification of parity-odd effects in compound nuclear resonances. Experiments confirm that parity-odd amplitudes in nucleon–nucleon interactions are amplified by several orders of magnitude at certain p-wave resonances in heavy nuclei populated by eV to keV energy neutrons. ¹ Random matrix theory has been used successfully to analyze the width of the distribution of those parity-odd asymmetries, since part of the amplification mechanism can be traced to the chaotic nature of the nuclear states involved. ²