Subleading Isgur-Wise form factors from QCD sum rules.

In the hea.vy-qua.& effective theory, current matrix elements between two heavy pseudosca1a.r or vector mesons a.re pa.ra.metrized by a. set of universa.1 form factors. These functions are calcula.ted to. suhlea.ding order in the l/nz~ expansion using QCD sum rules. The equa.tions of motion and Wa.rd ident,ities of the effective theory are incorpora,ted in the analysis. Within this approa.ch, pa.ra.meter-free predictions are obtained for all form fa.ctors a.t zero recoil. The results allow for an almost model-independent analysis of current-induced transitions between heavy mesons. As an a.pplica.tion, the l/rnC a.nd l/m* corrections to the ha.dronic form factors describing semileptonic B + D !u and B + D*Cu decays are computed. The possibility of extra.cting I& from these processes is discussed, and the importance of a measurement of symmetry-viola.ting effects in ratios of factors is pointed out.