Abstract
The longitudinal momentum distributions of one- and two-neutron removal fragments ( ) of from the reaction with a C target at 72 MeV have been measured for the first time using a new direct time-of-flight method with nearly full acceptance for the breakup fragments. The unexpectedly narrow width of ( in FWHM) is consistent with two neutrons occupying the orbital in . This indicates modification of core ( ) structure for neutron halolike shell nuclei near the drip line. This also suggests the lowering of the s orbital providing a justification for the magic number.
- Received 20 September 2001
DOI:https://doi.org/10.1103/PhysRevLett.88.142502
©2002 American Physical Society