Isospin conservation and the independence hypothesis in the decay of 49V, 52Cr and 55Mn

Abstract

Energy spectra and angular distributions of protons and α-particles emitted in the decay of 49V, 52Cr and 55Mn produced by 14 MeV protons and 12–16 MeV α-particles were measured between 30° and 150°. The evaporation cross sections of the (p, p'), (p, α), (α, p) and (α, α') reactions were used to deduce the isospin mixing fractions, μ, between the T ⪢ and T < states of these compound nuclei and values of 0.2–0.3 were obtained. The ratio of upward to downward mixing was calculated to be ≈ 0.02. Values of the Coulomb matrix elements were deduced and found to range from ≈ 30 to 120eV. Measurements on the α and p ̃ exit channels permitted a test of the independence hypothesis and the latter was verified for 49V and 55Mn.