The Mesonic and Nonmesonic Decay Rates of the $_{\Lambda}$He$^{4}$

We calculated the lifetime and the mesonic and nonmesonic decay rates of the four body $_{\Lambda }$He$^{4}$ Hypernucleus by using Hyperspherical Functions method in momentum space for different Nucleon-Nucleon and Lambda Nucleon effective potentials. The effects of final-state interactions and possible three body $\Lambda {\rm N}{\rm N}$ decay contributions were studied in the context of a simple model of nucleon-stimulated decay.