An improved simple model for α decay half-lives

In this paper,using the a particle preformation probabilities Pα from Xu et al.[Xu and Ren,Nucl.Phys.A 760,303（2005）],which were extracted by fitting experimental half-lives of α decay,based on a phenomenological harmonic oscillator potential model（HOPM） [Bayrak,J Phys G 47,025102（2020）],refitting 178 α decay halflives of even-even nuclei obtained from the latest nuclear property table NUB ASE2020,we obtain the only one adjustable parameter V0=162.6 MeV in the HOPM,i.e.,the depth of nuclear potential.The corresponding root-meansquare（rms） deviation is σ=0.322.Furthermore,to consider the contribution of centrifugal potential to unfavored a decay half-lives,adding a new term■（d and l are the adjustable parameter and orbital angular momentum carried away by emitted α particle） to the logarithmic form of favored α decay half-lives under the HOPM framework,we propose an improved simple model（ISM） for calculating favored and unfavored a decay half-lives.Fitting the experimental half-lives of 205 unfavored a decay,we obtain d=0.381.The ISM is used to calculate the unfavored α decay half-lives of 128 odd-A and 77 odd-odd nuclei.The results improve by 54.2% and 53.6%,respectively,compared with HOPM.In addition,we extend the ISM to predict the a decay half-lives of 144 nuclei with Z=117,118,119,and 120.For comparison,the improved model with eight parameters（DUR） proposed by Deng et al.[Deng,Phys.Rev.C 101,034307（2020）] and the modified universal decay law（MUDL） proposed by Soylu et al.[Soylu,Nucl.Phys.A 1013,122221（2021）] are also used.The predictions of these models and/or formulas are generally consistent with each other.