Exclusive semileptonic decays of B mesons to orbitally excited D mesons   in the relativistic quark model
  Exclusive semileptonic B meson decays to orbitally excited D mesons are investigated in the infinitely heavy quark limit in the framework of the relativistic quark model based on the quasipotential approach. The B\to D^{**}e\nu Isgur-Wise functions \tau_{3/2}(w) and \tau_{1/2}(w) are determined. It is found that the relativistic transformation of the meson wave functions (Wigner rotation of the light quark spin) contribute already at the leading order of the heavy quark expansion. 
D. Ebert, R. N. Faustov, V. O. Galkin