Pionic decay of Λ hypernuclei in a continuum shell model

We evaluate pionic decay widths of \ensuremath{\Lambda} hypernuclei using a shell model for both the nuclear bound and continuum nucleon wave functions in the final state and distorted waves for the outgoing pion. An excellent agreement with the recent KEK measurement of ${\ensuremath{\pi}}^{\ensuremath{-}}$-decay widths of ${}_{\ensuremath{\Lambda}}^{12}\mathrm{C}$ and ${}_{\ensuremath{\Lambda}}^{28}\mathrm{Si}$ is found. In addition, results for ${}_{\ensuremath{\Lambda}}^{56}\mathrm{Fe}$ are consistent with the existing upper bound.