AUTHOR=Jones K. L. , Kovoor J. , Kanungo R. 

TITLE=Status of experimental knowledge on the unbound nucleus 13Be

JOURNAL=Frontiers in Physics

VOLUME=11

YEAR=2023

URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2023.1242668

DOI=10.3389/fphy.2023.1242668

ISSN=2296-424X

ABSTRACT=<p>The structure of the unbound nucleus <sup>13</sup>Be is important for understanding the Borromean, two-neutron halo nucleus <sup>14</sup>Be. The experimental studies conducted over the last four decades are reviewed in the context of the beryllium chain of isotopes and some significant theoretical studies. The focus of this paper is the comparison of new data from a <sup>12</sup>Be(d,p) reaction in inverse kinematics, which was analyzed using Geant4 simulations and a Bayesian fitting procedure, with previous measurements. Two possible scenarios to explain the strength below 1 MeV above the neutron separation energy were proposed in that study: a single p-wave resonance or a mixture of an s-wave virtual state with a weaker p- or d-wave resonance. Comparisons of recent invariant mass and the (d,p) experiments show good agreement between the transfer measurement and the two most recent high-energy nucleon removal measurements.</p>