On three-cluster resonance structure of hypernuclei $_Λ^{7}$He, $_Λ^{7}$Li and $_Λ^{7}$Be
The bound and resonance states of hypernuclei $_Λ^{7}$He, $_Λ^{7}$Li and $_Λ^{7}$Be are studied within a three-cluster model. Within this model, hypernuclei $_Λ^{7}$He, $_Λ^{7}$Li and $_{Λ}^{7}$Be are considered as three-cluster systems $^{4}$He+$^2n$+$Λ$, $^{4}$He+$d$+$Λ$, $^{4}$He+$^2p$+$Λ$, respectively. Special attention is paid to determining resonance states in the three-cluster continuum of these hypernuclei and to study their nature. One semi-realistic nucleon-nucleon potential is employed to determine the internal structure of the clusters $^{4}$He, $^2n$, $d$ and $^2p$, and their interaction. Three versions of the nucleon-hyperon potential, known as the YNG potential, are employed to determine the interaction of the listed clusters with the lambda hyperon. A set of very narrow and fairly wide resonance states is found in the three-cluster continuum of $_Λ^{7}$He, $_Λ^{7}$Li and $_Λ^{7}$Be. The narrowest resonance states were detected in $_Λ^{7}$He and $_Λ^{7}$Li and their total width does not exceed 10 keV. The dominant decay channels of these resonance states are revealed.