Isotopic spin selection rules X: The 7.18 MeV state of 20 Ne

Abstract

The possible E1 transition between the 3– state at 7.18 MeV and the 2+ state at 1.63 MeV in ²⁰Ne is forbidden by the isotopic spin rule. It has been sought using the reaction ¹⁶O(α, γ)²⁰Ne and it has been shown that the radiative width is less than 6 MeV. This corresponds to ∥ M ∥² ⩽4.3×10^×5 in Weisskopf Units or to contaminations α² ₀(1) ⩽1.3×10^×3 of the 7.18 and 1.63 MeV states with T = 1 states.