EXPERIMENTAL SEARCH FOR THE KAONIC NUCLEAR STATE K-pp

Abstract

We search for the most basic kaonic nuclear state, K-pp, by studying an exclusive p + p → p + Λ + K+ process at Tp = 3.1 GeV using FOPI apparatus at GSI, Darmstadt, Germany. A possible signature of the K-pp is searched as a p + p → K-pp + K+ → p + Λ + K+ reaction in the event sample of pΛK+ three body process. A missing-mass ΔM(K+) spectrum, a Λp invariant-mass M(Λp) spectrum and a mono energetic kaon will characterize such a two body process. The reaction channel is basically the same as the one which T. Yamazaki et al. very recently reported a possible hint of such state with M = 2267 MeV /c2 and Γ = 118 MeV from a re-analysis of the DISTO experiment data. The DISTO data was taken at Tp = 2.85 GeV . The beam energy of the FOPI experiment is chosen to optimize the signal to background ratio and also to see the background shape separately. FOPI data taking took place in August-September 2009 and analysis is currently undergoing.