Nonperturbative QCD contributions to the semileptonic decay width of theBmeson

Publisher Website
Google Scholar
Abstract
Nonperturbative QCD contributions to the inclusive semileptonic decay of the B meson consist of the dynamic and kinematic components. We calculate the decay width in an approach based on light-cone expansion and heavy quark effective theory, which is able to include both components of nonperturbative QCD contributions. The kinematic component results in the phase-space extension and is shown to be quantitatively crucial, which could increase the decay width significantly. We find that the semileptonic decay width is enhanced by long-distance strong interactions by +(9±6)%. This analysis is used to determine the CKM (Cabibbo-Kobayashi-Maskawa) matrix element |Vcb| with a controlled theoretical error. Implications of the phase-space effects for the nonleptonic decay widths of b hadrons are briefly discussed. The experimental evidence for the phase-space effects is pointed out.