Role of 2p-2h states in weak 0 +−0 − transitions in A = 16 nuclei

Abstract

Muon-capture and β-decay rates for the transitions 16O(0 +, ground) (a3) 16N(0 −, 120 keV) are calculated to second order in perturbation theory. With a one-boson-exchange residual interaction, reasonable agreement to the decay rates Λ μ and Λ β can be achieved, but only if meson-exchange corrections are incorporated in the transition operator. These corrections strongly influence the time-like part of the axial-vector current.