Abstract

NAKAMURA, T. Breakup Reactions of Neutron Halo Nuclei. Rev. mex. fis. [online]. 2006, vol.52, suppl.1, pp.35-40. ISSN 0035-001X.

We present experimental studies of breakup reactions of one-neutron halo nucleus ¹¹ Be and two-neutron halo nucleus ¹¹ Li with carbon and lead targets at approximately 70 MeV/nucleon at RIKEN. In the Coulomb breakup of 1¹Be, the selection of forward scattering angles has been found useful to extract the first-order E1 Coulomb breakup component, and to exclude the nuclear contribution and higher-order Coulomb breakup components. This angle-selected energy spectrum is thus used to deduce the spectroscopic factor for the halo configuration in ¹¹Be, which has been found to be 0.72 ± 0.04. In the breakup of ¹¹ Be with the carbon target, we have observed excitations to the discrete states at E_x = 1.78 MeV and E_x = 3.41 MeV. Angular distributions for these states show the diffraction pattern characteristic of L = 2 transitions. In the Coulomb breakup of ¹¹ Li we have observed the strong E1 excitation at E_rel ~ 300 keV, which is very different from the previous observations. The non-energy weighted sum of E1 strength indicates the strong neutron-neutron correlations in ¹¹ Li.

Keywords : Spectroscopic factor; spin; parity; isobaric spin.