Eur. Phys. J. C (1998) 1: 221-233
https://doi.org/10.1007/BF01245811

Inclusive semileptonic decays of polarized Λ_b Baryons into polarized τ-leptons

¹ Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099, Mainz, Germany
² Department of Physics, Technion-Israel Institute of Technology, 32000, Haifa, Israel

Received: 3 April 1997
Published online: 27 February 2005

Abstract

We employ OPE techniques within HQET to calculate the inclusive semileptonic decays of polarized Λ_b baryons. Lepton mass effects are included which enables us to also discuss rates into polarized τ-leptons. We present explicit results for the longitudinal polarization of the τ in the Λ_b rest frame as well as in the (τ⁻, v_τ) c.m. frame. In both the Λ_b rest frame and in the (τ⁻, v_τ) c.m. frame we make use of novel calculational techniques which considerably simplify the calculations. The transverse polarization components of the τ are calculated in the (τ⁻, v_τ) c.m. frame. We delineate how to measure the full set of 14 polarized and unpolarized structure functions of the decay process by angular correlation measurements. A set of observables are identified that allow one to isolate the contributions of the twoO(1/m _t ²) nonperturbative matrix elementsK _b and ε_b.