The α-width of the lowest T = 2 state in 28Si

Abstract

We have studied the E x = 15.22 MeV, J π = 0 + T = 2 level in 28Si as an isospin forbidden resonance in 24Mg(α, α 0) 24Mg and obtained Γ α, c.m. = 222 ± 22 eV. This corresponds to a reduced width ≈ 1.4 × 10 −4 times the Wigner limit, which is the largest known reduced α 0 width of a 0 + T = 2 state in the A = 4 n T z = 0 nuclei. We have also established the existence of a J π = 0 + state at E x = 15.12 MeV with Γ c.m. = 11 ± 2 keV and Γ x/ Γ = 0.7 ± 0.1. Narrow resonances at E x = 15.08, 15.29 and 15.31 MeV are also observed.