Abstract :
Recently experiments were performed in Dubna (Russia) and RIKEN (Japan) to study 5H, 7H, and 8He. The 5H state at ∼ 1.8 MeV above the t + 2n threshold was observed in the reactions p(6He, 2He)5H and t(t,p)5H. The experimental evidence for existence of 7H state near the t + 4n threshold was obtained in study of the p(8He, 2He)7H reaction. Investigation of the p(8He, t) reaction populating the ground and excited 2+-state of 6He show that the 8He ground state has a structure containing the 6He subsystem in the excited 2+ state with a large weight.
