Tri-nucleon cluster structure in 6He and 6Be

Tri‐nucleon molecular structures in 6He and 6Be were investigated by using the 6Li(7Li,7Be)6He reaction at 455 MeV and 6Li(3He,t)6Be reaction at 450 MeV, respectively. Binary decay into t+t from a broad state at Ex = 18.0 ± 1.0 MeV in 6He and into 3He+3He from one at Ex = 18.0 ± 1.2 MeV in 6Be, were observed by measuring tri‐nucleon cluster‐decays in coincidence with reaction‐particles. The branching ratios for binary decay were estimated to be about 0.7 for both 6He and 6Be. From the angular correlations of decay particles, these states are assigned to be P states.