Anomalous population of He10 states in reactions with Li11
Abstract
Structure with the lowest energy observed in the He10 spectrum populated in the proton knockout reaction with a Li11 beam has a peak at 1.2to1.5 MeV. This peak is usually interpreted as a resonant 0+ ground state of He10. Our theoretical calculations indicate that this peak is likely to be a superposition of 1-, 0+, and 2+ excitations with very similar shapes. Moreover, the "soft" 1- excitation appears to be the lowest in energy. Such an anomalous continuum response is traced to the halo structure of Li11 providing an extreme low energy shift to all the expected continuum excitations. Competition between effects on the spectrum of the initial-state structure and of the final-state interaction and three-body correlations in He10 are discussed. The analogous effect of an extreme low-energy shift could also be expected in other cases of 2n emitters populated in reactions with halo nuclei. A simplified example of the He10 spectrum in α knockout from Be14 is given. We also discuss limits on the properties of He9 stemming from the observed He10 spectrum.
- Publication:
-
Physical Review C
- Pub Date:
- August 2014
- DOI:
- 10.1103/PhysRevC.90.024610
- arXiv:
- arXiv:1403.1748
- Bibcode:
- 2014PhRvC..90b4610S
- Keywords:
-
- 24.50.+g;
- 21.10.Gv;
- 25.40.Sc;
- 27.20.+n;
- Direct reactions;
- Mass and neutron distributions;
- Spallation reactions;
- 6<
- =A<
- =19;
- Nuclear Theory
- E-Print:
- 10 pages, 13 figures