Lifetimes of Light Hyperfragments. II

We have continued our studies of the lifetimes of light hyperfragments. Our analysis is based on a total sample of 1476 mesonic decays of hyperfragments, of which 77 decayed in flight. The values we found for the mean lives are the following: $\tau \left({}_{\Lambda }{}^{}{}_{}{}^{}\mathrm{H}_{}^3{}_{}{}^{}\right)=\left({{2.85}_{-1.05\mathrm{}}}^{+1.27\mathrm{}}\right)\times {10}^{-10\mathrm{}}$ sec, using both two-body and three-body decays; $\tau \left({}_{\Lambda }{}^{}{}_{}{}^{}\mathrm{H}_{}^4{}_{}{}^{}\right)=\left({{2.68}_{-1.07\mathrm{}}}^{+1.66\mathrm{}}\right)\times {10}^{-10\mathrm{}}$ sec, using only three-body decays; $\tau \left({}_{\Lambda }{}^{}{}_{}{}^{}\mathrm{He}_{}^4{}_{}{}^{}\right)=\left({{2.28}_{-1.29\mathrm{}}}^{+2.33\mathrm{}}\right)\times {10}^{-10\mathrm{}}$ sec; $\tau \left({}_{\Lambda }{}^{}{}_{}{}^{}\mathrm{He}_{}^5{}_{}{}^{}\right)=\left({{2.51}_{-0.73\mathrm{}}}^{+1.90\mathrm{}}\right)\times {10}^{-10\mathrm{}}$ sec; and $\tau \left({}_{\Lambda }{}^{}{}_{}{}^{}\mathrm{He}_{}^{4,5}{}_{}{}^{}\right)=\left({{2.43}_{-0.43\mathrm{}}}^{+0.60\mathrm{}}\right)\times {10}^{-10\mathrm{}}$ sec for the combined mean life of all the ${}_{\Lambda }{}^{}{}_{}{}^{}\mathrm{He}_{}^4{}_{}{}^{}$ and ${}_{\Lambda }{}^{}{}_{}{}^{}\mathrm{He}_{}^5{}_{}{}^{}$ events. The last lifetime quoted contains only a statistical error. The others, in addition, contain in their errors the effects due to uncertainties in our knowledge of the bias for two-body events and of the separation of ambiguous three-body events. All the results are in good agreement with theoretical calculations of hyperfragment lifetimes.