α-particle preformation factors in heavy and superheavy nuclei*

Abstract

In the present work, the α-particle preformation in heavy and superheavy nuclei from {220}{Th} to {294}{Og} have been investigated. Combing the experimental α decay energies and half-lives, the α-particle preformation factors Pα are extracted from the ratios between theoretical α decay half-lives calculated by Two-Potential Approach (TPA) and experimental data. It is found that the α-particle preformation factors show the obvious odd-even staggering behavior and unpaired nucleons will inhibit α-particle preformation. Meanwhile, it is also found that both the α decay energy and the mass number of parent nucleus show considerable regularity with the extracted experimental α-particle preformation factors. After considering the major physical factors, a local phenomenological formula with only five valid parameters for α-particle preformation factors Pα is proposed. This analytic expression not only has clear physical meaning but also has good precision. As an application, this analytic formula is extended to estimate the α-particle preformation factors and further predict the α decay half-lives for unknown even-even nuclei with Z = 118 and 120.