Improved Estimates for Processes $b\to s{l}^{+}{l}^{-}$, $B\to k{l}^{+}{l}^{-}$, and $B\to k^{*}{l}^{+}{l}^{-}$

We present the complete calculation for the short-distance flavor-changing process $b\to s{l}^{+}{l}^{-}$ and discuss the effect of QCD enhancement, and the resulting $e-\mu$ rate difference. We estimate the exclusive rates for $B\to k{l}^{+}{l}^{-}$ and $B\to k^{*}{l}^{+}{l}^{-}$ using the relativistic constituent-quark model to calculate the different form factors that include recoil effects. The effect of the fourth generation in enhancing the rates is also discussed.