Abstract
The unbound excited states of the neutron drip-line isotope have been investigated via the reaction in inverse kinematics at a beam energy of . The decay energy spectrum of was reconstructed from the momenta of and the neutron. The spin parity of the first excited state, observed at , was determined to be from the angular distribution of the cross section. Higher-lying states were also observed. The quadrupole transition parameter of the state was deduced, for the first time, to be . The relatively high excitation energy and small value are indicative of the shell closure in .
- Received 27 February 2012
DOI:https://doi.org/10.1103/PhysRevLett.109.022501
© 2012 American Physical Society