QCD sum rules on the light cone and B→π form factors

Abstract

The semileptonic decay B→π_lν is one of the most important reactions for the determination of the CKM matrix element |Vub|. However, in order to extract |Vub| from data one needs an accurate theoretical calculation of the hadronic matrix element describing the B to π transition. QCD sum rules, based on operator product expansion on the light cone, provide a reliable approach to achieve this aim. QCD corrections and higher twist contributions can be taken systematically into account.