New approach for measuring ‖Vub‖ at futureBfactories

It is suggested that the measurements of hadronic invariant mass (${\mathit{m}}_{\mathit{X}}$) distributions in the inclusive B→${\mathit{X}}_{\mathit{c}\left(\mathit{u}\right)}$lν decays can be useful in extracting the CKM matrix element ‖${\mathit{V}}_{\mathit{u}\mathit{b}}$‖. We investigated hadronic invariant mass distributions within the various theoretical models of HQET, FAC, and the chiral Lagrangian as well as the ACCMM model. It is also emphasized that the ${\mathit{m}}_{\mathit{X}}$ distributions even at the region ${\mathit{m}}_{\mathit{X}}$>${\mathit{m}}_{\mathit{D}}$ in the inclusive b→u are effective in selecting the events, experimentally viable at the future asymmetric B factories, with better theoretical understanding.