Moments in inclusive semileptonic B meson decays at the Belle experiment

Abstract

Since my return to Austria in the year 2003, I have measured observables in inclusive B meson decays at the Belle experiment and worked together with theorists on the interpretation of these measurements in terms of the Cabibbo–Kobayashi–Maskawa matrix element |Vcb|. And in fact, only this memorial book project made me fully aware of Kolya Uraltsev's ground breaking theoretical contributions to this field. He was not a theorist who talked a lot to an experimentalist like me, and maybe this is not a bad thing for good science. I certainly remember his enthusiasm from conferences, e.g., when I was powerless to keep his presentation to the scheduled time as a session chair at the CKM2005 workshop in San Diego. Still I feel there is some amount of irony in the fact, that I know so little about a person whose work has been so decisive for my career in high energy physics. To commemorate Kolya Uraltsev's pioneering work on inclusive semileptonic B meson decays B → Xcℓν and on the Heavy Quark Expansion (HQE), which has already been paid tribute to in other articles in this volume, I will review the measurement of the electron energy and the hadronic mass moments in B → Xcℓν decays performed at the Belle experiment. These measurements allow to both test his theoretical calculations and to extract |Vcb| and non-perturbative quantities, such as the b-quark mass, from his formulae.