Attempt to connect the nuclear charge radii with the experimental α decay data for superheavy nuclei

Abstract

Abstract. Significant progresses have been made so far for the synthesis of the heaviest elements, while the knowledge of them appears to be quite limited even when it comes to basic properties, e.g., their size. On the other side, the observation of α decay chains is the main tool to identify the newly produced elements. In this report, we propose to make use of the available experimental α decay data to extract the nuclear charge radii of superheavy nuclei. Within the density dependent cluster model, the nucleon density distribution of the target nucleus is determined by exactly reproducing the measured α decay half-life of its parent, finally leading to the nuclear radii. Encouraged by the agreement between theory and experiment for heavy nuclei, we extend the study to the region of superheavy nuclei as well. Background and motivationWith the advent of improved facilities and technologies, a great deal of experimental efforts have been devoted to synthesize the superheavy nuclei (SHN), leading to the makeup of nuclidic chart up to Z = 118 [1, 2]. The α decay chains are not only taken as the main source to identify the newly synthesized SHN, but also provide insight knowledge about their properties. As well known, there are available methods to measure the nuclear charge radius such as particles scattering on the target nuclei, Kα X rays, measurements of transitions energies in muonic atoms and optical isotopes shifts [3]. Unfortunately, the detection on the SHN radii is still difficult using these methods due to short lifetimes and tiny cross sections of heaviest nuclei. It is therefore interesting to employ an alternative approach using the available experimental α decay data to extract more information on structural properties, e.g., the nuclear charge radii, for superheavy nuclei. In fact, α decay has been taken as a tool to recognize the nuclear radii at an early stage of nuclear physics, despite the rough assumptions. Owing to the advanced experimental facilities and theoretical approaches, improved experimental data have been accumulated for the α decay process [1, 2, 4] and considerable progresses have also been made for the α decay calculations [5][6][7][8][9][10][11][12][13]. With these in mind, we propose to establish a bridge between the nuclear radii and the experimental α decay data. The main logic of the present model will be presented with initial results in the following section. * e-mail: qyibin@njust.edu.cn Brief introduction of theoretical approach and resultsGiven that the α decaying nucleus is pictured as an α particle interacting with an axially symmetric deformed core nucleus, the total α-core potential is composed of the nuclear and Coulomb terms,where θ is the orientation angle of the emitted α particle with respect to the symmetric axis of the core, and λ is the renormalization factor for the depth of nuclear potential. Based on the double folding integral, the nuclear and Coulomb potentials can be constructed as [14]υ(s = |r 2 + r − r 1 |), where υ(s) denotes the M3Y-Reid type nucle...