PIONIC-DECAY SPECTRA OF FEW-BODY LAMBDA-HYPERNUCLEI

Pionic-decay spectra are discussed in A=4 and 5 Lambda hypernuclei by using wave functions obtained by the resonating group method. For He-5 (Lambda), the pi(-) spectrum shows a sharp peak at 171 MeV with 1.5 Me V FWHM in the total pion energy. For H-4(Lambda) and He-4(Lambda), the spectra have broad peaks around 170 MeV with 6-7 MeV FWHM. This diffe rence is caused by resonance structures of the final-state nuclei unde r the spin-nonflip dominance in the pionic decay. Partial decay widths are calculated to check the normalization of the spectra, and are in systematically good agreement with all available experimental data.