The relative frequencies of the decay modes of positive k-mesons and the decay spectra of modes K_Μ3, Τ′ and K_Β

Some 3 300 K-meson decay events have been studied in a large stack exposed to the positive K-beam at the Berkeley 6 GeV Bevatron. The events have been selected in an unbiassed way and have been used to yield preliminary information concerning the shape of the energy spectrum of the charged particle emitted in the rarer 3-body decay-modes Τ′, κ (K_Μ3) and K_Β. The relative abundance of the, decaymodes has been estimated the results being summarized in the TableModeττ^′K_μ2χ(K_μ2)κ{script}(K_μ3)K_βAbundance (%)6.77±0.452.15±0.4257.0±2.623.2±2.25.9±1.35.1±1.3. The number of interactions observed over the first 4 cm from decay of the π-mesons secondary to κ-decay yields the surprisingly short estimate of the interaction M.F.P. of (11.1 ± 2.4) cm. This appears to be in significant disagreement with that found for artificial π⁺-mesons by other workers, namely 27 cm in the same energy region, (109 ÷ 82) MeV.