1994/12/31 by M. Shifman, M. SHIFMAN, N. G. Uraltsev +1 · 2 citations
Physics and Astronomy · #Neutrino Physics Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph
paper · pdf · doi:10.1142/s0217751x95002199
published as Int.J.Mod.Phys.A10:4705-4714,1995 · 9 pages, no figures, revised: One reference added and some styllistic changes made
arxiv created 1995/01/11 · openalex publication_date 1995/12/30 · arxiv updated 2010/11/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We comment on two recent calculations of the second order perturbative corrections in the heavy flavor semileptonic transitions within the Brodsky-Lepage-Mackenzie approach. It is pointed out that the results do not show significant enhancement either in the inclusive b→c decays or in the exclusive amplitudes at zero recoil provided that the expansion parameter is chosen in a way appropriate to the kinematics at hand. The values of the second order coefficients inferred from the BLM type calculations appear to be of order unity in both cases. Thus, in both cases no significant uncertainty in extracting V cb can be attributed to perturbative effects. The theoretical accuracy is mostly determined by the existing uncertainty in [Formula: see text] nonperturbative corrections in the exclusive B→D* amplitude, and, to a lesser extent, by the uncertainty in the estimated value of the kinetic energy matrix element [Formula: see text] in the case of Γ sl (b→c). The theoretical accuracy of the inclusive method of determining V cb seemingly competes with and even exceeds the experimental accuracy.