Mass measurements beyond the major r-process waiting point 80Zn

TL;DR

This study provides high-precision mass measurements of neutron-rich zinc isotopes, including the first experimental determination of 81Zn, enabling better understanding of the r-process nucleosynthesis pathway and astrophysical conditions.

Contribution

First experimental mass measurement of 81Zn, establishing 80Zn as a key waiting point in the r-process and confirming the N=50 shell closure far from stability.

Findings

Mass of 81Zn measured for the first time

80Zn identified as a major r-process waiting point

N=50 shell closure confirmed far from stability

Abstract

High-precision mass measurements on neutron-rich zinc isotopes 71m,72-81Zn have been performed with the Penning trap mass spectrometer ISOLTRAP. For the first time the mass of 81Zn has been experimentally determined. This makes 80Zn the first of the few major waiting points along the path of the astrophysical rapid neutron capture process where neutron separation energy and neutron capture Q-value are determined experimentally. As a consequence, the astrophysical conditions required for this waiting point and its associated abundance signatures to occur in r-process models can now be mapped precisely. The measurements also confirm the robustness of the N = 50 shell closure for Z = 30 farther from stability.