2002/05/15 by Adam K. Leibovich, Zoltan Ligeti, Mark B. Wise · 54 citations
Computer Science · Physics and Astronomy · #Computational Physics and Python Applications #Energy (signal processing) #Lepton #Matrix element #Order (exchange) #Particle physics theoretical and experimental studies #Point (geometry) #Quantum Chromodynamics and Particle Interactions #Semileptonic decay #Structure function #hep-ph
paper · pdf · doi:10.1016/s0370-2693(02)02097-x
published in Physics Letters B 539(3-4), 242-248 (Elsevier BV) · 12 pages
arxiv created 2002/05/15 · openalex publication_date 2002/07/01 · arxiv updated 2014/11/17 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The charged lepton spectrum in semileptonic B→ Xu ℓν decay near maximal lepton energy receives important corrections from subleading structure functions that are formally suppressed by powers of ΛQCD/mb but are enhanced by numerical factors. We investigate the series of higher order terms which smear over a region of width ΔE_ℓ ∼ ΛQCD near the endpoint the contributions proportional to δ(E_ℓ - mb/2) times (i) the matrix element of the chromomagnetic operator, and (ii) four-quark operators. These contribute to the total rate at the few percent level, but affect the endpoint region much more significantly. Implications for the determination of |Vub| are discussed.