Physics Letters B (Dec 2021)
Statistical fluctuations of negative parity levels in even mass nuclei
Abstract
This study presents the first statistical analysis on the correlation of negative parity states. All the available experimental data of 1−&2− levels of the even mass nuclei in the 16≤A≤212 mass region are used to prepare the sequences and classified as their masses. Random matrix theory together with a usual least - square procedure are used to extract the chaos measures of Berry – Robnik distribution function for different sequences in the framework of nearest neighbor spacing distribution. Also, we considered the chaotic degrees of these levels in relation to different modes of calculated deformations values and the shell model configuration of the last protons and neutrons of even mass nuclei. The results of this consideration suggest the most correlation of 1− levels in the A<50, mass area, but similar statistics of 2− levels are yield in the 150<A<200 region. The most GOE-like behavior of 1− levels is reported for sequences that the last protons lie in the d3/2 orbitals, and the neutrons filled the h9/2 orbitals, but for 2− levels, nuclei with 1h11/2 and 1i13/2 configurations for respectively, protons and neutrons, show the maximum correlation. Also, the results of this study suggest the most correlation of 1− levels for some mass regions which have the maximum values of the averaged quadrupole and hexacontatetrapole deformations.
