Subleading Isgur-Wise form factors and O(1/m_Q) corrections to the semileptonic decays B->D_1 l\bar\nu and B->D_2^* l\bar\nu

Abstract

Exclusive semileptonic decays B->D_1(2420)l\bar\nu and B->D_2^*(2460)l\bar\nu are studied at the subleading order of the heavy quark expansion. The subleading Isgur-Wise functions resulted from the kinetic energy and chromomagnetic corrections to the HQET Lagrangian are calculated by QCD sum rules in the framework of the heavy quark effective theory. The decay rates and branching ratios are computed with the inclusion of the order of 1/m_Q corrections. It is found that the 1/m_Q correction to the decay rate is not large for B->D^*_2 but is very large for B->D_1.