Inclusive Semileptonic B and Polarized Lambda_b Decays from QCD

Abstract

The differential decay spectrum $d\Gamma /d{E}_{e}d{q}^2$ for the semileptonic decay of an unpolarized hadron containing a b-quark, and the decay spectrum $d\Gamma /d{E}_{e}d{q}^{2}d\cos \theta$ for polarized ${\Lambda }_b$ decay are computed to second order in the $1/m_b$ expansion. Most of the $1/m_b^2$ corrections have a simple physical interpretation, which is discussed in detail. The implications of the results for the determination of $V_{ub}$ are discussed. The decay spectra for semileptonic decay of hadrons containing a c-quark are also given. There is a subtlety in the use of the equations of motion at order $1/m_b^2$ in the heavy quark expansion which is explained.

Comments: (46 pages, 8 figs, uses harvmac and uufiles), UCSD/PTH 93-14, CALT-68-1883 (REVISED VERSION: Some typos corrected, and one incorrect paragraph deleted)