Coupled channel appooach for pionic atoms 1H and 3He

Abstract The momentum-space method by Vincent and Phatak is extended to deal with a two-particle bound state, coupled to other open channels. The present approach is applied to two systems of coupled channels represented by π − p , π 0 n , γn and π − 3 He, π 0 3 H, γ 3 H, respectively. The energy shifts and absorption widths of the 1 s levels of pionic hydrogen and the 3 He gp-atom are calculated and compared with existing experimental data.