Exploring the Na+3n light nuclei via the (7Li,7Be) reaction

Experimental signatures of the dynamical correlations of a core with a single-particle neutron have been found in light neutron-rich nuclei investigated via the (7Li,7Be) charge-exchange reactions at around 8MeV=u. Of particular astrophysical relevance are low-lying narrow resonances (¡ » 200 keV FWHM) BSEC (Bound States Embedded in the Continuum). Because of their long lifetime BSEC states are likely to e®ect the capture rates in any scenario for nucleosynthesis in neutron-rich environment. They have been observed in the continuum of 11Be and 15C nuclei. A microscopic nuclear structure model based on QRPA theory, which takes into account Dynamical Core Polarisation (DCP) correlations, gives a suitable description of these resonances as well as single-particle states of the studied systems. In this context, high-energy narrow structures populated in nuclei having an integer number of ®-particles plus three neutrons are good BSEC candidates and can be systematically investigated.