Mass measurements of $^{60-63}$Ga reduce X-ray burst model uncertainties and extend the evaluated $\mathbf{T=1}$ isobaric multiplet mass equation

S.F. Paul , J. Bergmann , J.D. Cardona , K.A. Dietrich , E. Dunling , Z. Hockenbery , C. Hornung , C. Izzo , A. Jacobs , A. Javaji , B. Kootte , Y. Lan , E. Leistenschneider , E.M. Lykiardopoulou , I. Mukul , T. Murböck , W.S. Porter , R. Silwal , M.B. Smith , J. Ringuette , T. Brunner , T. Dickel , I. Dillmann , G. Gwinner , M. Maccormick (1) , M.P. Reiter , H. Schatz , N.A. Smirnova (2) , J. Dilling , A.A. Kwiatkowski

1 IJCLab - Laboratoire de Physique des 2 Infinis Irène Joliot-Curie
2 CENBG - Centre d'Etudes Nucléaires de Bordeaux Gradignan

We report precision mass measurements of neutron-deficient gallium isotopes approaching the proton drip line. The measurements of ${}^{60–63}\mathrm{Ga}$ performed with the TITAN multiple-reflection time-of-flight mass spectrometer provide a more than threefold improvement over the current literature mass uncertainty of ${}^{61}\mathrm{Ga}$ and mark the first direct mass measurement of ${}^{60}\mathrm{Ga}$. The improved precision of the ${}^{61}\mathrm{Ga}$ mass has important implications for the astrophysical $rp$ process, as it constrains essential reaction $Q$ values near the ${}^{60}\mathrm{Zn}$ waiting point. Based on calculations with a one-zone model, we demonstrate the impact of the improved mass data on prediction uncertainties of x-ray burst models. The first-time measurement of the ${}^{60}\mathrm{Ga}$ ground-state mass establishes the proton-bound nature of this nuclide, thus constraining the location of the proton drip line along this isotopic chain. Including the measured mass of ${}^{60}\mathrm{Ga}$ further enables us to extend the evaluated $T=1$ isobaric multiplet mass equation up to $A=60$.

Domaines: Physique Nucléaire Expérimentale [nucl-ex]; Astrophysique [astro-ph]

S.F. Paul, J. Bergmann, J.D. Cardona, K.A. Dietrich, E. Dunling, et al.. Mass measurements of $^{60-63}$Ga reduce X-ray burst model uncertainties and extend the evaluated $\mathbf{T=1}$ isobaric multiplet mass equation. Phys.Rev.C, 2021, 104 (6), pp.065803. ⟨10.1103/PhysRevC.104.065803⟩. ⟨hal-03476893⟩