Rare B-decays in QCD

We review theoretical work done on rare B-decays in the context of the Standard Model (SM) of electroweak interactions. The framework used is that of QCD, which is applied to calculate the decay rates and distributions in a number of processes, such as B → Xs + γ, B → Xd + γ, B → Xs + l+l-, and B → Xs + νν-bar, where Xs and Xd denote light hadrons with an overall quantum number S = -1 and S = 0, respectively. We particularly emphasize inclusive measurements in this sector, which would eventually permit a more reliable comparison of the SM predictions and experiments. However, we also discuss estimates of some exclusive rare B-decay modes, calculated in the vector meson dominance approximation and using the heavy quark effective theory (HQET). The importance of measuring the CKM-suppressed rare B-decays in determining the CKM matrix-element Vtd is underlined. Rate estimates in some inclusive and exclusive suppressed rare decay modes are presented by imposing current experimental constraints on the CKM matrix. (author). 61 refs, 11 figs, 9 tabs