Structure of $^{13}$Be probed via secondary beam reactions - IN2P3 - Institut national de physique nucléaire et de physique des particules Access content directly
Journal Articles Physical Review C Year : 2014

Structure of $^{13}$Be probed via secondary beam reactions

N.A. Orr
N.L. Achouri
N. Ashwood
  • Function : Author
T. Bloxham
  • Function : Author
B. A. Brown
  • Function : Author
W. N. Catford
  • Function : Author
N. Curtis
  • Function : Author
M. Freer
  • Function : Author
E. de Góes Brennand
  • Function : Author
P. Haigh
  • Function : Author
F. Hanappe
  • Function : Author
C. Harlin
  • Function : Author
J.L. Lecouey
  • Function : Author
  • PersonId : 829316
A. Ninane
  • Function : Author
N. Patterson
  • Function : Author
D. Price
  • Function : Author
J. S. Thomas
  • Function : Author

Abstract

The low-lying level structure of the unbound neutron-rich nucleus $^{13}$Be has been investigated via breakup on a carbon target of secondary beams of $^{14,15}$B at 35 MeV/nucleon. The coincident detection of the beam velocity $^{12}$Be fragments and neutrons permitted the invariant mass of the $^{12}$Be+$n$ and $^{12}$Be+$n$+$n$ systems to be reconstructed. In the case of the breakup of $^{15}$B, a very narrow structure at threshold was observed in the $^{12}$Be+$n$ channel. Contrary to earlier stable beam fragmentation studies which identified this as a strongly interacting $s$-wave virtual state in $^{13}$Be, analysis here of the $^{12}$Be+$n$+$n$ events demonstrated that this was an artifact resulting from the sequential-decay of the $^{14}$Be(2$^+$) state. Single-proton removal from $^{14}$B was found to populate a broad low-lying structure some 0.70 MeV above the neutron-decay threshold in addition to a less prominent feature at around 2.4 MeV. Based on the selectivity of the reaction and a comparison with (0-3)$\hbar\omega$ shell-model calculations, the low-lying structure is concluded to most probably arise from closely spaced J$^\pi$=1/2$^+$ and 5/2$^+$ resonances (E$_r$=0.40$\pm$0.03 and 0.85$^{+0.15}_{-0.11}$ MeV), whilst the broad higher-lying feature is a second 5/2$^+$ level (E$_r$=2.35$\pm$0.14 MeV). Taken in conjunction with earlier studies, it would appear that the lowest 1/2$^+$ and 1/2$^-$ levels lie relatively close together below 1 MeV.

Dates and versions

in2p3-00920222 , version 1 (18-12-2013)

Identifiers

Cite

G. Randisi, A. Leprince, H. Al Falou, N.A. Orr, F.M. Marqués, et al.. Structure of $^{13}$Be probed via secondary beam reactions. Physical Review C, 2014, 89, pp.034320. ⟨10.1103/PhysRevC.89.034320⟩. ⟨in2p3-00920222⟩
93 View
0 Download

Altmetric

Share

Gmail Mastodon Facebook X LinkedIn More