? Particle Preformation And Shell Effect In Heavy Nuclei

So far,118 elements and more than 2000 nuclides have been discovered.Most of these discovered nuclei are distributed along the ? stable line.With the increase of nuclear charge,the instability of decay and spontaneous fission increases with the rising coulomb force.However,the nuclear theory has predicted that there could be a stable island of superheavy nuclei beyond the tip of the known nuclear stable area.In order to find the center of the stable island,it is necessary to study the structural properties of the nuclei in the superheavy nuclear area.? decay,whose properties can provide a number of information about the structures of the mother nuclei,is one of the main decay channels of both heavy and superheavy nuclei.It may be a process in which ? particles are formed before the barrier penetrates,which called the ? particle preformation.The stability information of the mother nuclei can be obtained by extracting the probabilities of preformation which can be measurements to reflect the difficulty that the ? decay occurs.The research shows that the shell effect plays a key role in the ? particle preformation.The closer the proton and nucleon numbers are to the magic numbers,the more difficult the formation of ? cluster inside the mother nucleus is.Recent studies show that the subshell closure may not exist at Z = 92 and N = 126,which gives us a strong motivation to explore the shell effect at Z = 92 and N = 126 by studying the ? particle preformation and predict the magic numbers of the superheavy nuclei.The potential energy curves during the ? decay process are given within GLDM in this papar,the penetration probabilities are calculated with the WKB approximate and the preformation factors are extracted with respectively the experimental and theoretical decay energies and half-life periods.The theoretical decay energies are adopted from the finite-range liquid drop model(FRDM)and the half-life periods are estimated by the fomulas from G.Royer.The preformation factors of N = 126,128 isotones and Z = 84-92 isotopes indicate that the N = 126 shell closure is evidently weakened when Z = 92.By comparing the experimental preformation factors of U isotopes with the theoretical results,the variation trends are almost the same.Therefore,the magic numbers predicted by the theoretically calculated preformation factors in the region of superheavy nuclei are accurate to a certain extent.The calculations indicate that the proton magic numbers are probably present near Z = 108 to N = 152,162 isotones and Z = 116 to N = 176,184 isotones.The results also show that another subshell closure may exist after Z = 124 in the superheavy nuclei,which can be great theoretical evidence and guidance to the relevant experiments in the future.