Study On The Synthesis Of New Elements Z=119,Z=120 And New Nuclide ²⁹⁸Fl Within The Di-nuclear System Model

In recent years,the synthesis of new elements and nuclides is a frontier focus in the field of nuclear physics,and a large number of theoretical and experimental workers are competing to participate in it.At present,the main way to synthesize superheavy nuclei is through heavy ion fusion evaporation reaction.Thus,this paper systematically studies the mechanism of fusion evaporation reaction through the di-nuclear system(DNS)model,and calculates the evaporation residue cross section(ERCS)in the range of Z=112-118 under the framework of the DNS model.The results can well reproduce the experimental measurements,which also directly proves the reliability of the DNS model.Based on this,we reasonably predicted the optimal synthesis conditions of new elements Z=119,Z=120 and the predicted next possible double magic nucleus predicted by theory.In order to find the optimal synthesis conditions of new elements Z=119 and Z=120,we calculated some stable projectile-target combinations that may synthesize Z=119 and Z=120,and analyzed the effects of mass asymmetry and isospin effect of target nucleus on the ERCS.The calculation results show that for the synthesis of new element Z=119,the cross section is the largest when the fusion reaction 45Sc+248Cf evaporates three neutrons at the excitation energy of 39 MeV.For the synthesis of new element Z=120,the cross section is the largest when the fusion reaction 45Sc+252Es evaporates three neutrons at the excitation energy of 39 MeV.In addition,to synthesize the next double magic nucleus 304120 predicted by the relativistic mean-field model,some possible fusion reactions induced by radioactive beams are discussed.We found that the hot fusion reaction 50Ca+257Fm in the 3n evaporation channel is the best reaction to synthesize the superheavy nucleus 304120.In order to verify the next double magic nucleus predicted by the macroscopic-microscopic model is 298Fl,the structural properties and decay properties of Z=114 isotope chain and N=184 homoneutron chain in the superheavy nuclear region were calculated.It has been verified that 298Fl may be the next spherical double magic nucleus and also the center of the superheavy nuclear stable island.Due to the strong shell effect and long half-life of 298Fl,it is easy to detect once synthesized in the laboratory.However,at present,there is no stable projectile-target combination to synthesize such a neutron rich nuclide.Thus,based on the DNS model,we study the synthesis of superheavy nuclide by using the neutron rich radioactive beam.For the synthesis of new nuclide 298Fl,we propose to use the fusion reaction 64Ti+238U to evaporate four neutrons at the excitation energy of 43 MeV.Although the beam intensity of radioactive nuclear beam is lower than that of stable beam in most cases,and the use of stable nuclear beam is more conducive to the synthesis of superheavy nuclides,for the synthesis of such neutron-rich nuclides,it is still necessary to systematically study the fusion reaction induced by extremely neutron-rich radioactive beam,which will provide a lot of useful information for future experiments.