Alpha-Decay Studies of Rf, Sg, and Hs Isotopes within the Multi-Channel Cluster Model

Abstract

Besides α-decay energies and half-lives, more information on nuclear structure properties can be obtained from fine structure observed in α decay. The multi-channel cluster model (MCCM) for well-deformed α emitters has very recently been proposed for a precise description of the α-decay fine structure. In this paper, based on the newly proposed Q α formula and the predicted rotational energy for superheavy nuclei, we present a theoretical prediction of the fine structure in the α decay of deformed Rf, Sg, and Hs isotopes within the MCCM. The branching ratios to various daughter states and total α-decay half-lives are evaluated by the five-channels microscopic calculations. Any adjustable parameter is not introduced in our calculations. This is, to our knowledge, the first coupled-channel study of the α-decay fine structure in superheavy nuclei. It is expected that the present predictions would be useful for ongoing or future experiments on structure researches of superheavy nuclei. §1. IntroductionAlpha decay is one of the most important decay channels of unstable nuclei. The experimental measured quantities are α-decay energies Q α and half-lives T 1/2 . The decay energies pose a tough test for nuclear mass models and provide information on the excitation energy of final daughter states. The half-lives provide information on the stability of nuclides. In particular, the location of nuclear shell closures in the superheavy mass region can be extracted by analyzing systematic trends in α-decay energies and half-lives. For example, the experimental data show that there exists the enhanced nuclear stability at N = 162, confirming the predicted N = 162 neutron shell closure. 1) Besides, an experimental combination of α decay and γ emission can greatly help the spectroscopic study of neutron-deficient nuclei. 2), 3) Identification and knowledge of new synthesized elements and nuclides wholly or mainly resort to observing α-decay chains. 4)-6) From the theoretical standpoint, thanks to the intensive interest in superheavy nuclei, lots of efforts have been devoted to pursue a precise interpretation of the α-decay half-lives of superheavy nuclei, such as the cluster model, 7), 8) generalized liquid drop model (GLDM), 9) density-dependent cluster model (DDCM), 10) super asymmetric fission model (SAFM), 11) unified model for α decay and α capture (UMADAC), 12) Coulomb and proximity potential model (CPPM), 13) densitydependent M3Y (DDM3Y) effective interaction, 14) and so on. Information on nuclear deformed shell closures in this region can be achieved through such α-decay studies. * )