The spin dependence of an weak interaction in the decay of hypernuclei

From an analysis of 468 hypernuclei (HFs) with ranges > 120 μm, the non-mesic to π^?-mesic ratio (Q^?) for_ΛHe and_ΛHe⁵ HFs was found to be 1.37 ±0.17 and 1.58± 0.20 respectively. This data, together with results on_ΛHe⁴ and heavy hypernuclei, has been used to deduce spin dependences for Λⁿ and ΛP weak interactions in decay of hypernuclei. It is found that the rates for triplet and singlet interactions between Λ and neutron are 22 Γ_Λ and 11 Γ_Λ and for Λ and proton are 8.2 Γ_Λ and 5.5 Γ_Λ respectively, where Γ_Λ is the decay rate of Λ. The total decay rates for ΛHe⁴ and_ΛHe⁵ are 1.28 Γ_Λ and 0.99 Γ_Λ and the non-mesic decay rates are 0.17 Γ_Λ and 0.51 Γ_Λ respectively.