Statistical errors in Weizsaecker-Skyrme mass model

TL;DR

This paper assesses the statistical uncertainties in the Weizs"acker-Skyrme mass model parameters and their impact on mass predictions, highlighting increased errors for neutron-rich nuclei and key parameters influencing these uncertainties.

Contribution

It introduces an efficient method to quantify statistical errors in model parameters and analyzes their effects on nuclear mass predictions, especially for neutron-rich nuclei.

Findings

Model errors are mostly smaller than discrepancies with experimental data.

Errors increase significantly for neutron-rich heavy nuclei near the drip line.

Symmetry energy coefficients strongly influence predictions for neutron-rich nuclei.

Abstract

The statistical uncertainties of 13 model parameters in the Weizs\"acker-Skyrme (WS*) mass model are investigated for the first time with an efficient approach, and the propagated errors in the predicted masses are estimated. The discrepancies between the predicted masses and the experimental data, including the new data in AME2016, are almost all smaller than the model errors. For neutron-rich heavy nuclei, the model errors increase considerably, and go up to a few MeV when the nucleus approaches the neutron drip line. The most sensitive model parameter which causes the largest statistical error is analyzed for all bound nuclei. We find that the two coefficients of symmetry energy term significantly influence the mass predictions of extremely neutron-rich nuclei, and the deformation energy coefficients play a key role for well-deformed nuclei around the $\beta$-stability line.