One of the strange particles observed in early bubble chamber experiments was Ξ, called the “cascade” particle. It was produced in the reaction,
Κ- + p → Κ+ + Ξ- …………………(1)
and it decayed through the cascade Ξ- → Λ + π- (2) followed by Λ → P + π- (3) .
(a) Draw quark-flow Feynman diagram for the reaction (1).
The quark configurations are Κ+(u sbar), Κ- (us), Ξ- (dss).
(b) Draw Feynman diagrams at quark level for the decays (2) and (3).
The quark configuration of Λ is uds.