QCD sum rule analysis of the decays B→${\mathit{Kl}}^{+}$${\mathit{l}}^{\mathrm{-}}$ and B→${\mathit{K}}^{\mathrm{*}}$${\mathit{l}}^{+}$${\mathit{l}}^{\mathrm{-}}$

We use QCD sum rules to calculate the hadronic matrix elements governing the rare decays B→K${\mathcal{l}}^{+}$ ${\mathcal{l}}^{\mathrm{-}}$ and B→${\mathit{K}}^{\mathrm{*}}$ ${\mathcal{l}}^{+}$ ${\mathcal{l}}^{\mathrm{-}}$ induced by the flavor-changing neutral current b→s transition. We also study relations among semileptonic and rare B→${\mathit{K}}^{\left(\mathrm{*}\right)}$ decay form factors. The analysis of the invariant mass distribution of the lepton pair in B→${\mathit{K}}^{\left(\mathrm{*}\right)}$ ${\mathcal{l}}^{+}$ ${\mathcal{l}}^{\mathrm{-}}$ and of the angular asymmetry in B→${\mathit{K}}^{\mathrm{*}}$ ${\mathcal{l}}^{+}$ ${\mathcal{l}}^{\mathrm{-}}$ provides us with interesting tests of the standard model and its extensions. © 1996 The American Physical Society.