B mesons

Abstract

B mesons are bound states of a b quark and a light anti-quark. While the binding is provided by the strong interaction B mesons can only decay by the weak interaction. Since the top quark mass is large, B mesons are the only mesons containg quarks of the third geneation and thus their decays provide a unique opportunity to measure the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements V cb , V ub , V ts , and V td which describe the couplings of the third generation of quarks to the lighter quarks. We review experimental results on masses, lifetimes and decays of B mesons. These include measurements of the inclusive production of charmed and non-charmed mesons and baryons, observations of semileptonic B decays, B- B mixing, B meson lifetimes, measurements of exclusive hadronic final states with charmed mesons, the search for exclusive hadronic final states without charmed mesons, the first observation of the decay B → K ∗γ which is described by an electromagnetic penguin diagram and measurement of the inclusive b → sγ rate. The theoretical implications of these results will be considered.