Precision Mass Measurements of 74-76Sr Using the Multiple Reflection Time-of-flight Mass Spectrometer at TITAN

We report precision mass measurements of 74-76Sr performed with the TITAN multiple-reflection time-of- flight mass spectrometer. This marks a first-time mass measurement of 74Sr and gives increased mass precision to both 75Sr and 76Sr, which were previously measured using storage ring and Penning trap methods, respectively. This completes the A = 74, T = 1 isospin triplet and gives increased precision to the A = 75, T = 1/2 isospin doublet, which are both the heaviest experimentally evaluated triplets and doublets to date. The new data allow us to evaluate coefficients of the isobaric multiplet mass equation for the first time at A = 74 and with increased precision at A = 75. With increased precision of 75Sr, we confirm the recent measurement reported by CSRe that was used to remove a staggering anomaly in the doublets. New ab initio valence-space in-medium similarity renormalization group calculations of the T = 1 triplet are presented at A = 74. We also investigate the impact of the new mass data on the reaction flow of the rapid proton capture process in type I x-ray bursts using a single-zone model.