Spectroscopy of 7Li in stopped pion absorption reactions
The structure of excited levels in the 7Li isotope is studied via inclusive and correlation measurements in the stopped π− meson absorption reactions 10B(π−, t)X and 12C(π−, dt)X, respectively. The experiment is conducted using a low-energy pion beam at the LAMPF meson factory. Analysis of the missing mass spectra reveals 7Li states with the resonance parameters (Ex, Γ) (4.7, 0.1), (6.6, 0.9), (7.3, 0.1), (9.1, 2.8), and (9.6, 0.4) MeV. A highly excited state with Ex ≈ 11.2 MeV (i.e., an isobar analog of 7He) is observed in the 10B(π−,t)X reaction. An excited state with Ex = 10.3 ± 0.1 MeV and γ = 1.8 ± 0.4 Mev is observed for the first time in the 12C(π−,dt)X reaction.