Three-Body ΛNN → nNN Nonmesonic Weak Decay Process of Λ Hypernuclei

The fundamental motivation to study the non-mesonic weak decay (NMWD) of Λ hypernuclei is that it provides the unique channel for the information of the baryon–baryon weak interaction in SU3f group. The relative strength of the two main channels of NMWD whose decay processes are the Λp → np and Λn → nn has been the long standing puzzle during last several decades. The puzzling status has been settled down recently with the Γn / Γp value converging to \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\sim 0.5}$$\end{document} . The large experimental values of Γn / Γp of the previous measurements turned out to be due to the surprisingly large contribution of the competing three-body NMWD, ΛNN → nNN process. This paper discusses about the first measurement of the branching ratio of the three-body NMWD process and the renormalized intra-nuclear cascade method adopted to disentangle the contribution of the three-body process out of those due to final state interaction. And the prospects of the more accurate measurement of the three-body process also are presented.