Theoretical Study Of Nuclear ? Decay And Two-Proton Radioactivity

? decay and two-proton radioactivity studies are two hot topics in the modern nuclear physics field.Studing the phenomenon of a decay and two-proton radioactivity of atomic nuclei can obtain a wealth of nuclear structural properties and nuclear mass.This is of great significance for the synthesis of superheavy nuclei,the exploration of stable islands for superheavy nuclei,and the study of the properties of nuclei near the proton drip line.In this work,based on a generalized liquid drop model and the relativistic Hartree-Bogoliubov mean field model,the a decay preformation probabilities of nuclei near the shell are studied.Based on the two-potential approach and the cluster-formation model,the a decay halflives of the medium and heavy mass nuclei are systematically studied,and the a decay half-lives of the superheavy nucleus being synthesized experimentally and next neutron magic number are predicted.At the same time,based on the new Geiger-Nuttall law and Gamow-like model,this work systematically study the half-lives of the two-proton radioactive nuclei near the proton drip line,and predict the half-lives of the possible two-proton radioactive nuclei.The main tasks completed are as follows:(1)Based on a generalized liquid drop model,the ? decay preformation probabilities Pa of 152 nuclei near the shell with the proton number Z=82 and the neutron numbers N=126 are systematically studied.The results show that there are obvious linear relationships between Pa and the product of the valence proton(holes)Np and the valence neutron(holes)Nn,and the corresponding analytical formulas and parameters are given.The calculated a decay half-lives of 152 nuclei are in good agreement with the experimental data.In addition,extracting the Pa values calculated by Sun et al.in the relativistic Hartree-Bogoliubov mean field model,the linear relationship between P? and NpNn are still exist.Current work also further infers that this linear relationship is not model dependent,but may be related to the valence proton-neutron interaction near the closed shell.(2)Based on the two-potential approach and the cluster-formation model,the a decay half-lives of 170 even-even nuclei with Z=60-118 are calculated.Among them,the cluster-formation model is a microscopic model proposed based on quantum mechanics.According to the principle of state superposition,the Pa of the a decay nuclei can be given.The results show that the calculated a decay half-lives are in good agreement with the experimental half-lives.In addition,the a decay half-lives of Z=104-128 superheavy nuclei is predicted,these nuclei are being synthesized experimentally.The predicted results are in the middle of the predicted results of UDL and SemFIS.This proves the good predicted ability of our theoretical model.Finally,it is predicted that N=178 may be the next neutron magic number.(3)Based on the Geiger-Nuttall law,a two-parameter empirical formula is proposed to systematically study the half-lives of 8 two-proton radioactive nuclei(including 3 not true two-proton radioactive nuclei and 5 true two-proton radioactive nuclei).In addition,the Gamow-like model has been extended to the study of the half-lives of two-proton radioactivity.The research results show that the calculated results of the two-parameter empirical formula and Gamow-like model can reproduce the experimental data very well.In addition,the two-parameter empirical formula and Gamow-like model are used to predict the half-lives of 22 possible twoproton radioactive nuclei,and the predicted results are very consistent with the predicted results of other models.Finally,a brief summary and some outlooks are given.