Statistical features of the thermal neutron capture cross sections

Abstract

We discuss the existence of huge thermal neutron capture cross sections in several nuclei. The values of the cross sections are several orders of magnitude bigger than expected at these very low energies. We lend support to the idea that this phenomenon is random in nature and is similar to what we have learned from the study of parity violation in the actinide region. The idea of statistical doorways is advanced as a unified concept in the delineation of large numbers in the nuclear world. The average number of maxima per unit mass, $$ in the capture cross section is calculated and related to the underlying cross section correlation function and found to be $= 3/(\pi \sqrt{2}\gamma_{A})$, where $\gamma_{A}$ is a characteristic mass correlation width which designates the degree of remnant coherence in the system. We trace this coherence to nucleosynthesis which produced the nuclei whose neutron capture cross sections are considered here.Comment: 7 pages, 6 figures. To appear in Acta Physica Polonica B as a Contribution to the proceedings of:Jagiellonian Symposium of Fundamental and Applied Subatomic Physics, June 7- 12, 2015 Krakow, Polan