Abstract :
In order to determine the ratio of CKM matrix elements |VubVcb| (and |Vub|, we propose a new m method based on the heavy quark effective theory, which is theoretically described by the phase space factor and the well-known perturbative QCD correction only. In the forthcoming asymmetric B-experiments with microvertex detectors, BABAR and BELLE, the total separation of b → u semileptonic decays from the dominant b → c semileptonic decays would be experimentally viable. We explore the possible experimental option: the measurement of inclusive hadronic invariant mass distributions. We also clarify the relevant experimental backgrounds.
