Determination of the CKM matrix by semileptonic rare B-decays

The possibility to test the unitarity triangle of CKM matrix is examined by using the semileptonic rare $B$ decays, $B\to X_q{\text{l}}^{+}{\text{l}}^{-}$ with $q=d,s$ and $\text{l}$’s are leptons. The discussion is emphasized on the CP asymmetry in the framework of standard and beyond the standard models. For the beyond standard model, a minimal extension of the standard model containing an additional isosinglet charge (-1/3) charge quark, which leads to a deviation from CKM unitarity, is considered. As the results, in the standard model the CP asymmetry is visible only for $B\to X_d{\text{l}}^{+}{\text{l}}^{-}$, while in the latter model it is sizeable even for $B\to X_s{\text{l}}^{+}{\text{l}}^{-}$.