Improved radial basis function approach with odd-even corrections

The radial basis function (RBF) approach has been used to improve the mass predictions of nuclear models. However, systematic deviations were found between the improved masses and the experimental data for nuclei with four different odd-even parities of (Z, N), i.e., (even Z, even N), (even Z, odd N), (odd Z, even N), and (odd Z, odd N). In this work, we show that such deviations can be eliminated to a large extent by separately training the RBF for the groups of parities, resulting in a further improved predictive power of nuclear mass models and in particular single-nucleon separation energies. With this new RBF approach, the root-mean-square mass deviation for the latest version of the Weizsacker-Skyrme model WS4, falls to 135 keV with respect to known data. This is approaching the chaos-related unpredictability limit (similar to 100 keV).