W-exchange contribution in hadronic decays of bottom baryon

The nonleptonic decays of Λ_{b} that are dominated by W exchange are studied. In particular, the decay modes \varLambda_{b}\to\varDelta^{0}D^{0},\varDelta^{-}D^{+},Σ^{-}D_{s}^{+}, Λ_{b}\toΣ_{c}^{+}π^{-},Σ_{c}^{*0}π^{0},Ξ_{c}^{*0}K^{0} and \varLambda_{b}\toΣ_{c}^{+}π^{-} are analyzed. In an another aspect, the decay Λ_{b}\toΛ_{c}^{+}π^{-} in the factorization anstaz is studied. It is shown that factorization contributes to parity-violating (s-wave) amplitude A only. Hence factorization gives asymmetry parameter α=0. However, the dominant contribution to parity conserving (p-wave) amplitude B comes from W exchange, i.e., from the baryon pole, giving asymmetry parameter α=-0.77.