Test of nuclear mass models

Abstract

The reliability and prediction ability of 8 global nuclear mass models is systematically analyzed in terms of the accuracy of the model and the new neutron magic number predicted by experiments based on the ground-state nuclear mass data from AME2016. The root-mean-square (RMS) deviations of nuclear mass predicted by 8 nuclear mass models are calculated by subregion, and find that the Bhagwat and WS4 models possess better accuracy to describe the existing experimental data. By analyzing the trend of the neutron shell energy gap varying with neutron number, it is found that the KTUY, WS3 and WS4 models can well represent the mutation behavior caused by the new magic number <i>N</i> = 32, and it is predicted that <i>N</i> = 32 is likely to be a new magic number in the Cl isotope chain and Ar isotope chain. By analyzing the variation trend of α decay energy in the superheavy region, it is found that the FRDM12, WS3 and WS4 models can reproduce the phenomena of subshell with <i>N</i> = 152 and <i>N</i> = 162 well, and predict the relatively long life of nuclei at the neutron number <i>N</i> = 184 for the isotope chain with proton number <i>Z</i> = 108—114. The comprehensive analysis shows that the mass model with good accuracy cannot reproduce shell evolution behavior. For example, the Bhagwat model has the same accuracy as the WS4 model, but it cannot reproduce the mutation behavior of the new magic number <i>N</i> = 32, 152 and 162. But the KTUY model and FRDM12 model can reproduce the new magic number behavior of <i>N</i> = 32, 152 and 162, respectively, although the RMS deviation is slightly larger. The RMS deviation of WS4 model is small and can describe the shell evolution behavior in the nuclear mass well.