A model independent determination of |Vub|

It is shown that measuring the lepton invariant mass spectrum in inclusive semileptonic (B) over bar --> X(u)l<(nu)over bar> decay yields a model independent determination of \V-ub\. Unlike the lepton energy and hadronic invariant mass spectra, nonperturbative effects are only important in the resonance region, and play a parametrically suppressed role when d Gamma/dq(2) is integrated over q(2) > (m(B) - m(D))(2), which is required to eliminate the charm background. Perturbative and nonperturbative corrections are presented to order alpha(s)(2)beta(0) and Lambda(QCD)(2)/m(b)(2), and the Lambda(QCD)(3)/m(b)(3) corrections are used to estimate the uncertainty in our results. The utility of the (B) over bar --> X(s)l(+)l(-) decay rate above the psi(2S) resonance is discussed. (C) 2000 Elsevier Science B.V. All rights reserved.