A simple model for two-proton radioactivity

In this work,considering the preformation factor of the emitted two protons in parent nucleus S_(2p) and the effect of the parent nucleus deformation,based on the Wentzel-Kramers-Brillouin approximation and Bohr-Sommerfeld quantization condition,we improve a simple phenomenological model proposed by Bayrak[J.Phys.G:47,025102(2020)]to systematically study 2p radioactivity half-lives.This model contains two adjustable parameters V_(0) and a_(β),which are related to the depth of nuclear potential and effect of deformation.The calculated results show that this model can effectively reproduce the experimental data with a corresponding root-mean-square(RMS)standard deviation of σ=0.683.For comparison,we include the Gamow-like model(GLM)proposed by Liu et al.[Chin.Phys.C 45,044110(2021)],generalized liquid drop model(GLDM)proposed by Cui et al.[Phys.Rev.C 101,014301(2020)],effective liquid drop model(ELDM)proposed by M.Gonalves et al.[Phys.Lett.B 774,14(2017)],two-potential approach with Skyrme-Hartree-Fock(TPASHF)proposed by Pan et al.[Chin.Phys.C 45,124104(2021)],phenomenological model with a screened electrostatic barrier(SEB)propoesed by Zou et al.[Chin.Phys.C 45,104101(2021)],unified fission model(UFM)proposed by Xing et al.[Chin.Phys.C 45,124105(2021)],Coulomb and proximity potential model for deformed nuclei(CPPMDN)proposed by Santhosh[Phys.Rev.C 104,064613(2021)],two-parameter empirical formula proposed by Liu et al.[Chin.Phys.C 45,024108(2021)],and four-parameter empirical formula proposed by Sreeja et al.[Eur.Phys.J.A 55,33(2019)].In addition,we use this model to 2p predict the radioactive half-lives of some possible potential nuclei whose 2p radioactivity are energetically allowed or observed but not yet quantified in NUBASE2020.