Systematic study of proton radioactivity based on the double-folding potential model*

Abstract We study proton radioactivity in proton-rich nuclei with within a semi-microscopic framework in which the emitted proton is described by a finite-size density distribution. Two proton-density prescriptions are considered, namely, Gaussian and Fermi profiles. When microscopic spectroscopic factors are combined with a double-folding potential based on finite-size proton and daughter densities, the Fermi-density prescription yields the best overall agreement with the experimental results, reducing the global root-mean-square deviation of to . In addition, a modified universal decay law that embeds the same spectroscopic factors yields an even smaller deviation, , providing a high-precision global description of proton-radioactivity half-lives. We construct the proton–daughter interaction by folding a Skyrme-type effective nucleon–nucleon interaction with finite-size proton densities and spherical daughter densities and evaluate proton-emission half-lives within the Wentzel–Kramers–Brillouin approximation for 39 known proton emitters in this region. State-dependent spectroscopic factors and obtained from relativistic mean-field plus Bardeen–Cooper–Schrieffer calculations are employed to account for proton preformation. Subsequently, we compare the calculated half-lives with experimental data and analyze the residuals by grouping them according to the minimum orbital angular momentum and based on whether the decay proceeds from the ground or isomeric state. Finally, we extend the universal decay law for proton emission (UDLP) by including an explicit spectroscopic-factor term, obtaining a modified formula (MUDLP) that provides a compact global parametrization of experimental proton-radioactivity half-lives. Using the best-performing semi-microscopic prescription together with the MUDLP parametrization, we provide conditional half-life estimates for several candidate proton emitters near the proton drip line, where the input values are taken from AME2020. These results provide quantitative reference values for future experimental searches for new proton-radioactive nuclei.