Two body non-leptonic ${\Lambda }_b$ decays in quark model with factorization ansatz

Abstract

The two body non-leptonic ${\Lambda }_b$ decays are analyzed in factorization approximation, using quark model, $\xi =1/N_c$ as a free parameter. It is shown that the experimental branching ratio for ${\Lambda }_b⟶\Lambda J/\psi$ restricts $\xi$ and this ratio can be understood for a value of $\xi$ which lies in the range $0\le \xi \le 0.5$ suggested by two body B meson decays. The branching ratios for ${\Lambda }_b⟶{\Lambda }_c{D}_s^{\ast }(D_s)$ are predicted to be larger than the previous estimates. Finally it is pointed that CKM-Wolfenstein parameter ${\rho }^2+{\eta }^2$, where $\eta$ is CP phase, can be determined from the ratio of widths of ${\Lambda }_b⟶\Lambda \bar{D}$ and ${\Lambda }_b⟶\Lambda J/\psi$ or that of ${\Lambda }_b⟶p{D}_s$ and ${\Lambda }_b⟶{\Lambda }_c{D}_s$ independent of the parameter $\xi$.

Comments: 18 pages, latex, 1 figure available on request, please send any questions or comments to riazs@dpc.kfupm.edu.sa