Investigation of excited states of 4He through deuteron-induced three-particle reactions on 6Li

Abstract

Excited states of 4He are investigated through final-state interactions in the three-particle reactions 6Li(d, α't) 1H, 6Li(d, α' 3He)n and 6Li(d, α'd) 2H with 52 MeV deuterons. In measuring the differential cross sections, the detector of the first outgoing particle was kept at a fixed position and the second detector scanned over a range of coplanar angles favouring 4He final-state interactions. The data are interpreted in terms of four isospin T = 0 excited states of 4He at 21.9, 25.5, 28.5 and 31.8 MeV with widths of 1.8, 2.9, 5.3 and 5.6 MeV, respectively. Only the 21.9 and the 25.5 MeV levels are particularly evident. Angular correlation data indicate J π = 0 + or 1 + for the level at 25.5 MeV. No evidence is found for a narrow state at 23.9 MeV reported by Franz and Fick.