The authors present a study of B decays into semileptonic final states containing charged and neutral D1(2420) and D*2(2460). The analysis is based on a data sample of 208 fb−1 collected at the?(4S) resonance with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. With a simultaneous fit to four different decay chains, the semileptonic branching fractions are extracted from measurements of the mass difference?m = m(D**)-m(D) distributions. Product branching fractions are determined to be?(B → D1°l+?{sub l}) x?(D1° → D*+?−) = (2.97 ± 0.17 ± 0.17) x 10−3,?(B+ → D*2°l+?{sub l}) x?(D*2° → D{sup (*)+}?−) = (2.29 ± 0.23 ± 0.21) x 10−3,?(B° → D1−{ell}+?{sub {ell}}) x?(D1− → D*°?−) = (2.78 ± 0.24 ± 0.25) x 10−3 and?(B° → D*2−{ell}+?{sub {ell}}) x?(D*2− → D{sup (*)0}?−) = (1.77 ± 0.26 ± 0.11) x 10−3. In addition they measure the branching ratio?(D*2 → D?°)/?(D*2 → D{sup (*)}?−) = 0.62 ± 0.03 ± 0.02.

Using a large data sample of p{bar p} collisions at {radical}s = 1.96 TeV recorded by the CDF and D0 detectors operating at Fermilab Tevatron, the orbitally excited B mesons B{sub 1} and B*{sub 2} are observed directly as two separate states in fully reconstructed decays to B{sup (*)}{pi}. The masses and the mass differences between the states are presented. In the charm system, the orbitally excited D mesons D{sub 1} and D*{sub 2} are observed in fully reconstructed decays to D{sup (*)}{pi}. Measurements of the product branching rates of semileptonic decays B {yields} {bar D}**{mu}{sup +}{nu}{sub {mu}}X and their ratio are presented. They also present the observation of the semileptonic decays B{sub s} {yields} {mu}{nu}D**{sub s} where the excited D**{sub s} states are reconstructed in the mode D**{sub s} {yields} D*K{sub S}{sup 0}.

We use the heavy quark effective theory to investigate the form factors that describe the semileptonic decays of a B meson into excited daughter mesons. For an excited daughter meson with charm, a single form factor is needed at leading order, while five form factors and two dimensionful constants are needed to order 1/m(sub)c in the heavy quark expansion. For non-charmed final states, a total of four form factors are needed at leading order. For the process B ->D^(*)Xlv, four form factors are also needed at leading order.