Charmless two-body anti-triplet $b$-baryon decays

We study the charmless two-body decays of $b$-baryons $(\Lambda_b$, $\Xi_b^-$, $\Xi_b^0)$. We find that ${\cal B}(\Xi_b^-\to \Lambda \rho^-)=(2.08^{+0.69}_{-0.51})\times 10^{-6}$ and ${\cal B}(\Xi_b^0\to \Sigma^+ M^-)=(4.45^{+1.46}_{-1.09},11.49^{+3.8}_{-2.9},4.69^{+1.11}_{-0.79},2.98^{+0.76}_{-0.51})\times 10^{-6}$ for $M^-=(\pi^-,\rho^-,K^-,K^{*-})$, which are compatible to ${\cal B}(\Lambda_b\to p \pi^-,p K^-)$. We also obtain that ${\cal B}(\Lambda_b\to \Lambda\omega)=(2.30\pm0.10)\times 10^{-6}$, ${\cal B}(\Xi_b^-\to\Xi^- \phi,\Xi^- \omega)\simeq {\cal B}(\Xi_b^0\to\Xi^0 \phi,\Xi^0 \omega)=(5.35\pm0.41,3.65\pm0.16)\times 10^{-6}$ and ${\cal B}(\Xi^-_b\to\Xi^{-} \eta^{(\prime)})\simeq {\cal B}(\Xi^0_b\to \Xi^0 \eta^{(\prime)})=(2.51^{+0.70}_{-0.46},2.99^{+1.16}_{-0.57})\times 10^{-6}$. For the CP violating asymmetries, we show that ${\cal A}_{CP}(\Lambda_b\to p K^{*-})={\cal A}_{CP}(\Xi_b^-\to \Sigma^0(\Lambda)K^{*-})={\cal A}_{CP}(\Xi_b^0\to \Sigma^+K^{*-})=(19.7\pm 1.4)\%$. Similar to the charmless two-body $\Lambda_b$ decays, the $\Xi_b$ decays are accessible to the LHCb detector.