Semileptonic B Decays into Excited Charmed Mesons ($D_1$, $D_2^{\ast }$) in HQEFT

Abstract

Exclusive semileptonic B decays into excited charmed mesons ($D_1$, $D_2^{\ast }$) are studied up to the order of $1/m_Q$ in the framework of the heavy quark effective field theory (HQEFT), which contains the contributions of both particles and antiparticles. Two wave functions ${\eta }_0^b$ and ${\eta }_0^c$, which characterize the contributions from the kinematic operator at the order of $1/m_Q$, are calculated by using QCD sum rule approach in HQEFT. Zero recoil values of other two wave functions ${\kappa }_1^{\prime }$ and ${\kappa }_2^{\prime }$ are extracted from the excited charmed-meson masses. Possible effects from the spin-dependent transition wave functions which arise from the magnetic operators at the order of $1/m_Q$ are analyzed. It is shown that the experimental measurements for the branching ratios of $B\to D_{1}l\nu$ and $B\to D_2^{\ast }l\nu$ can be understood in the framework of HQEFT.

Comments: 27 pages, RevTex, 4 figures, 3 tables, to be published in IJMPA