Hadronic Weak Decay $\mathcal{B}_{b}(\frac{1}{2}^+) \to \mathcal{B}(\frac{1}{2}^{+},\; \frac{3}{2}^{+}) +V$

Abstract

It is shown that for the effective Lagrangian with factorization ansatz considered here, the two body hadronic decay $\mathcal{B}_{b}(\frac{1}{2}^+) \to \mathcal{B}(\frac{1}{2}^{+},\; \frac{3}{2}^{+}) + V$, for $\mathcal{B}_{b}(\frac{1}{2}^{+})$ belonging to the representation $\bar{3}$, only allowed decay channel is $\mathcal{B}_{b}(\frac{1}{2}^+) \to \mathcal{B}(\frac{1}{2}^{+})+ V$, where $\mathcal{B}(\frac{1}{2}^{+})$ belongs to the representation $8$ of $SU(3)$. However, for $\mathcal{B}_{b}(\frac{1}{2}^{+})$ belonging to the sextet representation $6$, the allowed decay channels are $\mathcal{B}_{b}(\frac{1}{2}^+) \to \mathcal{B}(\frac{1}{2}^{+},\; \frac{3}{2}^{+}) + V$, where $\mathcal{B}(\frac{1}{2}^{+})$ and $\mathcal{B}(\frac{3}{2}^{+})$ belongs to the octet representation $8^{\prime}$ and the decuplet $10$ of $SU(3)$, respectively. The decay channel $\mathcal{B}_{b}(\frac{1}{2}^+) \to \mathcal{B}(\frac{1}{2}^{+}) + V$ is analyzed in detail. The decay rate ($\Gamma$) and the asymmetry parameters $\alpha\;, \alpha^{\prime}\;, \beta\;, \gamma$ and $\gamma^{\prime}$ are expressed in terms of four amplitudes. In particular for the decay $\Lambda_b \to \Lambda + J/\psi$ it is shown that within the factorization framework, using heavy quark spin symmetry, the decay rate and the asymmetry parameters can be expressed in terms of two form factors $F_1$ and $F_{2}/F_{1}$, which are to be evaluated in some model. For other heavy quarks belonging to the triplet and sextet representation, the results can be easily obtained by using $SU(3)$ symmetry and phase space factor. Finally, the decay $\Omega_{b}^{-} \to \Omega^{-} + J/\psi$ is analyzed within the factorization framework. It is shown that the asymmetry parameter $\alpha$ in this particular decay is zero. The branching ratio obtained in the first approximation is compared with the experimental value.