Mass Measurements of Neutron-Rich Gallium Isotopes Refine Production of Nuclei of the First r-Process Abundance Peak in Neutron Star Merger Calculations

• Published in: arXiv.org 2020-01
• Main Authors: Reiter, M P, S Ayet San Andrés, Nikas, S, Lippuner, J, Andreoiu, C, Babcock, C, Barquest, B R, Bollig, J, Brunner, T, Dickel, T, Dilling, J, Dillmann, I, Dunling, E, Gwinner, G, Graham, L, Hornung, C, Klawitter, R, Kootte, B, Kwiatkowski, A A, Lan, Y, Lascar, D, Leach, K G, Leistenschneider, E, Martínez-Pinedo, G, McKay, J E, Paul, S F, W R Pla\ss, Roberts, L, Schatz, H, Scheidenberger, C, Sieverding, A, Steinbrügge, R, Thompson, R, Wieser, M E, Will, C, Welch, D
• Format: Article
• Language: English
• Subjects: Abundance; Atomic properties; Binary stars; Gallium isotopes; Neutron stars; Neutrons; Nuclei (nuclear physics); Star mergers; Uncertainty
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1810.11561

We report mass measurements of neutron-rich Ga isotopes \(^{80-85}\)Ga with TRIUMF's Ion Trap for Atomic and Nuclear science (TITAN). The measurements determine the masses of \(^{80-83}\)Ga in good agreement with previous measurements. The masses of \(^{84}\)Ga and \(^{85}\)Ga were measured for the first time. Uncertainties between \(25-48\) keV were reached. The new mass values reduce the nuclear uncertainties associated with the production of A \(\approx\) 84 isotopes by the \emph{r}-process for astrophysical conditions that might be consistent with a binary neutron star (BNS) merger producing a blue kilonova. Our nucleosynthesis simulations confirm that BNS merger may contribute to the first abundance peak under moderate neutron-rich conditions with electron fractions \(Y_e=0.35-0.38\).