Refining the nuclear mass surface with the mass of $^{103}$Sn

TL;DR

This study uses high-precision mass spectrometry to refine the masses of neutron-deficient tin isotopes, revealing inconsistencies with previous data and suggesting a smoother nuclear mass surface near the N=50 shell closure.

Contribution

The paper provides more accurate mass measurements for $^{103}$Sn and related isotopes, challenging previous estimates and improving the understanding of the nuclear mass surface near doubly-magic nuclei.

Findings

Mass uncertainty of $^{103}$Sn reduced by a factor of 4

New mass excess for $^{103}$Sn is -67104(18) keV

Overall smoothening of the nuclear mass surface observed

Abstract

Mass measurements with the ISOLTRAP mass spectrometer at CERN-ISOLDE improve mass uncertainties of neutron-deficient tin isotopes towards doubly-magic $^{100}$Sn. The mass uncertainty of $^{103}$Sn was reduced by a factor of 4, and the new value for the mass excess of -67104(18) keV is compared with nuclear \textit{ab initio} and density functional theory calculations. Based on these results and local trends in the mass surface, the masses of $^{101,103}$Sn, as determined through their $Q_{\textrm{EC}}$ values, were found to be inconsistent with the new results. From our measurement for $^{103}$Sn, we extrapolate the mass excess of $^{101}$Sn to -60005(300) keV, which is significantly more bound than previously suggested. By correcting the mass values for $^{101,103}$Sn, we also adjust the values of $^{104}$Sb, $^{105,107}$Te, $^{108}$I, $^{109,111}$Xe, and $^{112}$Cs near the proton drip line which are connected through their $\alpha$- and proton $Q$-values. The results show an overall smoothening of the mass surface, suggesting the absence of deformation energy above the ${N=50}$ shell closure.