Shell-model study on properties of proton dripline nuclides with Z, N = 30-50 including uncertainty analysis

TL;DR

This study uses shell-model calculations combined with statistical uncertainty analysis to predict the properties and stability of proton-rich nuclides with Z, N from 30 to 50, extending the known nuclear dripline.

Contribution

It introduces new formulas for binding energies with systematic uncertainty estimates and applies bootstrap methods for stability predictions in proton-rich nuclides.

Findings

Proposed binding energy formulas with ~0.3 MeV uncertainty.

Predicted a new nuclear dripline extending the proton-rich boundary.

Identified 30 nuclides stable against proton emission.

Abstract

The binding energies and proton separation energies of nuclides with $Z, N = 30-50$ are investigated, based on the shell model with an uncertainty analysis through statistical methods. Several formulas are used to obtain the binding energies and proton separation energies according to the shell-model calculations. The non-parametric Bootstrap method is applied to establish an uncertainty decomposition and recomposition framework. Moreover, it is used to estimate the stability of proton(s) emission for each nuclide. Two formulas for calculating the binding energies with a systematic uncertainty of $\sim0.3$ MeV are proposed, and a reliable extrapolation ability is examined. These binding energy formulas deduce similar forms of respective $S_{p}$ and $S_{2p}$ energies, which predict the extension of the nuclear boundary of this region. A nice description of the binding energies and proton separation energies is provided. The one- and two-proton separation energies and partial half-lives of proton emitting are predicted, thus showing a new dripline. Besides, there are 30 unstable nuclides predicted to be bound against proton(s)-emission. These nuclear properties will be useful in nuclear astrophysics.