The production of cascade particles by 5.5 GeV/c pions

The first observed production of negative cascade particles at an accelerator is reported. A 30 in. propane bubble chamber was exposed to a beam of negative pions of 5.5 GeV/c. Two cascades were identified, indicating a production cross section of 2.3−1.6+3.1 µb. TheQ values found were (49.5±7.9) MeV and (53.6±11.3) MeV. The lifetimes were (1.9±0.1) · 10−10 s and (5.2±0.4) · 10−10 s. Both Θ’s were produced backwards in the center-of-momentum system. The identification process and background is discussed.