A New Model-independent Method of Determining |V_{ub}/V_{cb}|

In order to determine the ratio of CKM matrix elements |V_{ub}/V_{cb}| (and |V_{ub}|), we propose a new model-independent 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.