PI-MESONIC WEAK DECAY-RATES OF LIGHT-TO-HEAVY HYPERNUCLEI

Pionic decays of light-to-heavy Lambda-hypernuclei are summarized incl uding a review and the updated estimates which are based on the pion d istorted waves generated by a sophisticated full-form optical potentia l. For heavy hypernuclei, the pion distortion effects yield a remarkab le enhancement as large as two orders of magnitudes in comparison with the estimate without any distortion, where the Coulomb distortion is found to play an important role. The systematic calculations for all t he sd-shell hypernuclei (including the updated p-shell results) predic t that the total pi(0) and pi(-) decay rates vary strikingly depending on the structures of individual hypernucleus and final nucleus. It is also shown by presenting the excitation functions that the partial pi onic decay is selective enough to be utilized as a hypernuclear spectr oscopic tool.