Astromeric nature of 119m-Ag unveiled through direct mass measurement

F. Rivero, M. Brodeur, J. Clark, B. Liu, G. W. Misch, M. Mumpower, W. S. Porter, D. Ray, G. Savard, T. M. Sprouse, A. A. Valverde, D. P. Burdette, A. Cannon, A. T. Gallant, A. M. Houff, K. Kolos, F. Kondev, R. Orford, C. Quick, K. S. Sharma, L. Varriano

Submitted submitted (2025)

The abundance of elements heavier than iron produced via the astrophysical rapid-neutron capture process depends sensitively on the atomic mass of the involved nuclei as well as the behavior of a few special types of nuclear isomers called astromers. High-precision mass measurements of 119Cd, 119Ag and their respective isomeric states have been performed with the Phase Imaging-Ion Cyclotron Resonance (PI-ICR) method with a precision of δm/m≈10−8 using the Canadian Penning Trap (CPT). The ground state mass excess, as well as the excitation energy, agrees with recent Penning Trap measurements from JYFLTRAP. Network calculations using these new measurements revealed that, contrary to previous expectations, 119mAg behaves as an astromer which significantly affects the population of 119Ag.