Neutron-unbound resonant states of 11Be were populated in neutron knock-out reactions from 12Be and identified by 10Be-n coincidence measurements. A resonance in the decay-energy spectrum at 80(2) keV was attributed to a highly excited unbound state in 11Be at 3.949(2) MeV decaying to the 2+ excited state in 10Be. A knockout cross section of 15(3) mb was inferred for this 3.949(2) MeV state suggesting a spectroscopic factor near unity for this 0p3/2- level, consistent with the detailed shell model calculations.
@article{arxiv.1104.0255,
title = {Neutron knockout of 12Be populating neutron-unbound states in 11Be},
author = {William A. Peters and T. Baumann and B. A. Brown and J. Brown and P. A. DeYoung and J. E. Finck and N. Frank and K. L. Jones and J. -L. Lecouey and B. Luther and G. F. Peaslee and W. F. Rogers and A. Schiller and M. Thoennessen and J. A. Tostevin and K. Yoneda},
journal= {arXiv preprint arXiv:1104.0255},
year = {2011}
}
Comments
5 pages, 2 figures \pacs{29.38.Db, 29.30.Hs, 24.50.+g, 21.10.Pc, 21.10.Hw, 27.20.+n} \keywords{neutron decay spectroscopy, neutron-unbound states in 11Be}