We perform the simultaneous $|V_{ ub}|$ and $|V_{ cb}|$ extractions with only the exclusive $\Lambda_b$ decays of $\Lambda_b\to (p,\Lambda_c^+)\mu\bar \nu_\mu$, $\Lambda_b\to p\pi^-$ and $\Lambda_b\to \Lambda_c^+ (\pi^-, D^-)$. We obtain that $|V_{ ub}|=(3.7\pm 0.3)\times 10^{ -3}$ and $|V_{ cb}|=(45.9\pm 2.7)\times 10^{ -3}$. Our value of $|V_{ ub}|$ is larger than that of $(3.27\pm 0.15\pm 0.16\pm 0.06)\times 10^{ -3}$, previously extracted by the LHC Collaboration from the exclusive $\Lambda_b$ decays also, but nearly identical to $(3.72\pm 0.19)\times 10^{ -3}$ from the exclusive $B$ decays. On the other hand, our extracted result of $|V_{ cb}|$ favors the value of $(42.2\pm 0.8)\times 10^{ -3}$ from the inclusive $B$ decays.
Categories: hep-ph hep-ex