Systematic calculations of α-decay half-lives with an improved empirical formula

Based on the recent data in NUBASE2012, an improved empirical formula for evaluating alpha-decay half-lives is presented, in which the hindrance effect resulting from the change of the ground state spins and parities of parent and daughter nuclei is included, together with a new correction factor for nuclei near the shell closures. The calculated alpha-decay half-lives are found to be in better agreement with the experimental data, and the corresponding root-mean-square (rms) deviation is reduced to 0.433 when experimental Q-values are employed. Furthermore, the Q-values derived from different nuclear mass models are used to predict alpha-decay half-lives with this improved formula. It is found that the calculated half-lives are very sensitive to the Q-values. Remarkably, when mass predictions are improved with the radial basis function (RBF), the resulting rms deviations can be significantly reduced. With the mass prediction from the latest version of Weizsacker-Skyrme (WS4) model, the rms deviation of alpha-decay half-lives with respect to the known data falls to 0.697.