V-ub from the hadronic invariant mass spectrum in semileptonic B decay

The hadronic invariant mass spectrum for the inclusive charmless semileptonic decay B --> X(u)e<(nu)over bar>(e) is studied, Particular attention is paid to the region s(H) < m(D)(2), which may be useful for extracting the value of \V-ub\. The sensitivity of the 2 spectrum to the parameter <(Lambda)over bar> m(B) - m(b) is explored. Perturbative d Gamma/ds(H) of order alpha(s)(2) beta(0) are calculated. For S-H similar to <(Lambda)over bar>m(b) nonperturbative QCD effects are important and the shape of the invariant mass spectrum is controlled by the B meson matrix element of an infinite sum of local operators. The utility of the hadronic mass spectrum for extracting \V-ub\ is explored. (C) 1997 Published by Elsevier Science B.V.