Electromagnetic transitions in near-threshold resonances

Abstract

Near-threshold collectivization of continuum shell model eigenstates is investigated in ${}^{20}$O on the example of B(E$\lambda$) decays of 4${}^{+}$ states in the vicinity of elastic and inelastic neutron threshold. Changes of the electromagnetic transition probabilities as a function of the continuum-coupling strength are explained by the corresponding evolution of the double poles of the scattering matrix.

Comments: 10 pages, 5 figures, Invited presentation at the XXXVI Mazurian Lakes Conference on Physics, September 1-7, 2019, Piaski, Poland