Direct Mass Measurements to Inform the Behavior of $^{128\mathrm{m}}\mathrm{Sb}$ in Nucleosynthetic Environments

Direct Mass Measurements to Inform the Behavior of ${}^{128 m}{Sb}$ in Nucleosynthetic Environments

D. E. M. Hoff, K. Kolos, G. W. Misch, D. Ray, B. Liu, A. A. Valverde, M. Brodeur, D. P. Burdette, N. Callahan, J. A. Clark, A. T. Gallant, F. G. Kondev, G. E. Morgan, M. R. Mumpower, R. Orford, W. S. Porter, F. Rivero, G. Savard, N. D. Scielzo, K. S. Sharma, K. Sieja, T. M. Sprouse, and L. Varriano

Phys. Rev. Lett. 131, 262701 – Published 27 December 2023

Abstract

Nuclear isomer effects are pivotal in understanding nuclear astrophysics, particularly in the rapid neutron-capture process where the population of metastable isomers can alter the radioactive decay paths of nuclei produced during astrophysical events. The $β$ -decaying isomer ${}^{128 m}{Sb}$ was identified as potentially impactful since the $β$ -decay pathway along the $A = 128$ isobar funnels into this state bypassing the ground state. We report the first direct mass measurements of the ${}^{128}{Sb}$ isomer and ground state using the Canadian Penning Trap mass spectrometer at Argonne National Laboratory. We find mass excesses of $- 84564.8 (25) keV$ and $- 84608.8 (21) keV$ , respectively, resulting in an excitation energy for the isomer of 43.9(33) keV. These results provide the first key nuclear data input for understanding the role of ${}^{128 m}{Sb}$ in nucleosynthesis, and we show that it will influence the flow of the rapid neutron-capture process.

Received 29 January 2023
Revised 25 July 2023
Accepted 13 November 2023

DOI:https://doi.org/10.1103/PhysRevLett.131.262701

Physics Subject Headings (PhySH)

Nuclear astrophysics r process

Radioactive beams Shell model

Nuclear Physics

Authors & Affiliations

D. E. M. Hoff ¹, K. Kolos ¹, G. W. Misch², D. Ray^3,4,*, B. Liu ^4,5, A. A. Valverde ^3,4, M. Brodeur⁵, D. P. Burdette⁴, N. Callahan⁴, J. A. Clark⁴, A. T. Gallant¹, F. G. Kondev ⁴, G. E. Morgan^4,6, M. R. Mumpower ^2,7,8, R. Orford⁹, W. S. Porter⁵, F. Rivero⁵, G. Savard^4,10, N. D. Scielzo ¹, K. S. Sharma ³, K. Sieja ¹¹, T. M. Sprouse², and L. Varriano ^4,10

¹Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, California 94550, USA
²Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
³Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
⁴Physics Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
⁵Department of Physics and Astronomy, University of Notre Dame, Notre Dame, Indiana 46556, USA
⁶Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA
⁷Center for Theoretical Astrophysics, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
⁸Joint Institute for Nuclear Astrophysics-Center for the Evolution of the Elements, Michigan State University, East Lansing, Michigan 48824, USA
⁹Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
¹⁰Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
¹¹Université de Strasbourg, IPHC, 23 rue du Loess 67037 Strasbourg, France CNRS, UMR7178, 67037 Strasbourg, France