Precision mass measurement of $^{173}$Hf for nuclear structure of $^{173}$Lu and the $\gamma$ process

TL;DR

This study precisely measured the mass of $^{173}$Hf, refining nuclear data crucial for understanding the $ extgamma$ process and nuclear reactions involving hafnium and lutetium isotopes.

Contribution

The paper provides a highly precise mass measurement of $^{173}$Hf, improving the accuracy of nuclear reaction rates relevant to astrophysical nucleosynthesis.

Findings

New mass-excess value agrees with literature but is nine times more precise.

Refined $Q_{EC}$ value rejects previous excited state assignments in $^{173}$Lu.

Reduced uncertainties in the $^{174}$Hf$( extgamma,n)$^{173}$Hf reaction rate for the $ extgamma$ process.

Abstract

We report on the precise mass measurement of the $^{173}$Hf isotope performed at the Ion Guide Isotope Separator On-Line facility using the JYFLTRAP double Penning trap mass spectrometer. The new mass-excess value, ${\mathrm{ME} = -55390.8(30)}$ keV, is in agreement with the literature while being nine times more precise. The newly determined $^{173}$Hf electron-capture $Q$ value, $Q_{EC} = 1490.2(34)$ keV, allows us to firmly reject the population of an excited state at 1578 keV in $^{173}$Lu and 11 transitions tentatively assigned to the decay of $^{173}$Hf. Our refined mass value of $^{173}$Hf reduces mass-related uncertainties in the reaction rate of $^{174}$Hf$(\gamma,n)^{173}$Hf. Thus, the rate for the main photodisintegration destruction channel of the $p$ nuclide $^{174}$Hf in the relevant temperature region for the $\gamma$ process is better constrained.