Semileptonic B decays to excited charmed mesons

Exclusive semileptonic B decays into excited charmed mesons are investigated at order Lambda(QCD)/m(Q) in the heavy quark effective theory. Differential decay rates for each helicity state of the four lightest excited D mesons (D-1, D-2*, D-0*, and D-1*) are examined. At zero recoil, Lambda(QCD)/m(Q) corrections to the matrix elements of the weak currents can be written in terms of the leading Isgur-Wise functions for the corresponding transition and meson mass splittings. A model independent prediction is found for the slope parameter of the decay rate into helicity zero D-1 at zero recoil. The differential decay rates are predicted, including Lambda(QCD)/m(Q) corrections with some model dependence away from zero recoil and including order alpha(s) corrections. Ratios of various exclusive branching ratios are computed. Matrix elements of the weak currents between B mesons and other excited charmed mesons are discussed at zero recoil to order Lambda(QCD)/m(Q). These amplitudes vanish at leading order, and can be written at order Lambda(QCD)/m(Q) in terms of local matrix elements. Applications to B decay sum rules and factorization are presented. [S0556-2821(98)02901-4].