Evidence for the $^{15}\text{Be}$ ground state from $^{12}$Be$+3$n events
Abstract
Background: Be is an unbound nuclide that has been observed to decay by one-neutron emission. Shell model calculations predict two low-lying states in its energy spectrum, however, only a single resonance has been observed from coincident measurements of Be+n. It has been suggested that the yet unobserved state may decay sequentially through the first excited state in Be followed by a two-neutron emission to Be. Purpose: The ground state of Be has yet to be confirmed. A search for this predicted Be state by reconstructing Ben events allows a possible determination of its ground state properties. Methods: A neutron-pickup reaction was performed with a Be beam on a CD target to populate unbound Be states. Decay energies were reconstructed using invariant mass spectroscopy by detecting Be daughter nuclei in coincidence with up to three neutrons. Results: Evidence for at least one resonance in Be is presented based on the reconstruction of Ben events. Through comparison with simulations, the energy of the strongest resonance in the analyzed reaction and decay channel is determined to be keV. Conclusions: The inclusion of a new Be state among the Be+n events lower in relative decay energy than the previous Be+n observations provides the best fit to the data. Because this suggested new state would be lower in energy than the previously observed state, it is a candidate for the ground state of Be.
Keywords
Cite
@article{arxiv.2411.04927,
title = {Evidence for the $^{15}\text{Be}$ ground state from $^{12}$Be$+3$n events},
author = {A. N. Kuchera and R. Shahid and J. Zhao and A. Edmondson and P. A. DeYoung and N. Frank and J. McDonaugh and O. Peterson-Veatch and W. F. Rogers and T. Redpath and M. Thoennessen},
journal= {arXiv preprint arXiv:2411.04927},
year = {2024}
}
Comments
Accepted to Physical Review C