We report data which imply the existence of a Σ-nucleus bound state, formed in a (K-, π-) reaction at rest on a 4He target. A peak was found, which we attribute to the formation of the Σ4He ground state, corresponding to ΔM≡M(4ΣHe)-M(4He)=267 .7±0.3 (statistical) -0.1+1.1 (systematic) MeV (BΣ+=3.2 MeV. The width of the peak was deduced to be 4.6±0.5 (statiscal) +1.6-1.3 (systematic) MeV. No clear peak was found in the corresponding region of the (K-, π+) spectrum. We assign I= 1 2 and S=0 to this state.
ASJC Scopus subject areas
- Nuclear and High Energy Physics