Beyond the neutron drip line: Use of final state interactions for identifying l=0 states in particle-unbound systems
Abstract
The unbound nuclear systems ^10Li and ^9He were produced in reactions of 28 MeV/u ^12,11,10Be incident on a ^9Be target. The charged fragment was deflected by a sweeper magnet to a scintillator array, while the time of flight of the neutron was measured with the NSCL's Neutron Wall. The distributions of the fragment-neutron velocity difference showed a strong influence of final-state interactions and also a significant influence of the initial state. The data were analyzed by expanding the initial bound single-particle state in continuum eigenstates of a Woods-Saxon potential. The essential results are a firm l=0 assignment for the lowest odd-neutron state in ^10Li and the first observation of a very similar state in ^9He, characterized by an s-wave scattering length more negative than -10 fm corresponding to an energy of the virtual state of less than 0.2 MeV. The reasons for the appearance of the 1s_1/2 intruder state as the ground state of the lightest N=7 isotones will be discussed.
- Publication:
-
APS Division of Nuclear Physics Meeting Abstracts
- Pub Date:
- October 2000
- Bibcode:
- 2000APS..DNP.JB001H