Two body non-leptonic $Λ_b$ decays in quark model with factorization ansatz

Abstract

The two body non-leptonic $Λ_b$ decays are analyzed in factorization approximation, using quark model, $ξ= 1 / N_c$ as a free parameter. It is shown that the experimental branching ratio for $Λ_b \longrightarrow Λ{J/ψ}$ restricts $ξ$ and this ratio can be understood for a value of $ξ$ which lies in the range $ 0 \leq ξ\leq 0.5 $ suggested by two body B meson decays. The branching ratios for $Λ_b \longrightarrow Λ_{c} D^*_s(D_s) $ are predicted to be larger than the previous estimates. Finally it is pointed that CKM-Wolfenstein parameter $ρ^2 + η^2$, where $η$ is CP phase, can be determined from the ratio of widths of $Λ_b \longrightarrow Λ\bar{D}$ and $Λ_b \longrightarrow Λ{J/ψ}$ or that of $Λ_b \longrightarrow p D_s$ and $Λ_b \longrightarrow Λ_c D_s$ independent of the parameter $ξ$.