The $\Lambda \overline{\Lambda }$ system produced in the reaction ${\pi }^{-}p\to n\Lambda \overline{\Lambda }$ at 6.0 and 7.0 GeV/c has been studied utilizing the ANL 1.5-m streamer-chamber facility. A 400 000-photograph exposure yielded 284 unweighted $n\Lambda \overline{\Lambda }$ events. The cross section for the reaction is 0.51±0.22≥b at 6.0 GeV/c and 1.21±0.23≥b at 7.0 GeV/c. No significant indications of baryonium states decaying into $\Lambda \overline{\Lambda }$ are found.

• Received 10 November 1980

DOI:https://doi.org/10.1103/PhysRevD.24.2347