Inclusive Semileptonic Decays and the Structure of B Mesons

A field theoretic description for inclusive semileptonic B meson decays is formulated. We argue that large regions of the phase spaces for the decays are dominated by distances near the light cone. The light-cone dominance allows to incorporate nonperturbative QCD effects in a distribution function. A one-to-one correspondence with the heavy quark effective theory is developed, which can estimate the first two moments of the distribution function. These conditions are useful but not restrictive enough to specify the distribution function, which must still be determined from experiment. Several model-independent predictions, such as scaling, sum rules of the hadronic structure functions and relations among them, are made. General formulas for the differential decay rates on several variables are presented, which are used for calculating the electron energy spectra with an Ansatz for the light-cone distribution function.