Feshbach Resonance due to Coherent Λ-Σ Coupling in 7ΛHe

Coherent Λ-Σ coupling effect in 7ΛHe is analyzed within three-body framework of two coupled channels, Λ-t-t and Σ-τ-t, where τ represents trinulceon which is either 3H or 3He. The hyperon-trinucleon (Yτ) and trinucleon-trinucleon (ττ) interactions are derived by folding G-matrices of YN and NN interactions with trinucleon density distributions. It is found that the binding energy of 7ΛHe is 4.04 MeV below the Λ+t+t threshold without Λ-Σ coupling and the binding energy is increased to 4.46 MeV when the coupling effect is included. This state is 7.85 MeV above the 6He+Λ threshold and it may have a chance to be observed as a Feshbach resonance in 7Li (e,e′K+) 7ΛHe experiment done at Jefferson Lab.