Radiative pion capture in 2H, 3He and 3H

We investigate the π– + 2H → γ + n + n, π– + 3He → γ + 3H, π– + 3He → γ + n + d, π– + 3He → γ + n + n + p and π– + 3H → γ + n + n + n capture reactions using realistic two-nucleon and three-nucleon potentials and the single nucleon Kroll-Ruderman-type transition operator. We obtain predictions for the total capture rates for all these processes, calculating rigorously the initial and final nuclear states.

Enhanced monopole and dipole transitions in nuclei induced by α cluster structures

Enhancement of the monopole and dipole transitions in the low-lying state is discussed on the basis of the microscopic and macroscopic α cluster models. Theoretical calculation clearly demonstrates that the strength of the monopole and dipole transitions are strongly enhanced by the excitation in the relative motion of the α cluster and the residual nucleus. The transition strength induced by the α excitation appears as the discrete distribution, and its excitation energy is much lower than the excitation energy of the single nucleon excitation, which is expected from the naive mean field picture.