Spectroscopy of the heavy lithium isotopes 10-12Li

Abstract

The experimental search for the production of heavy lithium isotopes 10-12Li was carried out in the stopped $\pi^{-}$ -meson absorption reactions on the radioactive target 14C. The study of 10Li was performed in the missing mass spectra in the 14C $ (\pi^{-},pt)X$ and 14C $ (\pi^{-},dd)X$ reactions. Three excited states of 10Li were identified. A broad state with a resonance energy $E_{r} = 6.13 \pm 0.11$ MeV has the highest excitation energy, compared with previously observed levels. The resonance parameters of three low-lying excited states of 11Li were determined in the 14C $ (\pi^{-}, pd)X$ reaction. In the 14C $ (\pi^{-},pp)X$ reaction an evidence for a 12Li excited state ( $ E_{r} = 4.0 \pm 0.2$ MeV and $ \Gamma = 1.1 \pm 0.2$ MeV) was found.