2001/05/22 by S. Groote, J. G. Körner, A. A. Pivovarov
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph
paper · pdf · doi:10.1103/physrevd.65.036001
published as Phys.Rev. D65 (2002) 036001 · 70 pages in LaTeX, 10 PostScript figures included in the text
arxiv created 2001/05/22 · openalex publication_date 2002/01/09 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We discuss the choice of weight functions for the moments of the spectral density for two-point correlators of hadronic currents over a finite energy interval. Of phenomenological relevance is an analysis of the spectra of \ensuremathτ lepton decay on the energy interval [0,M_\ensuremathτ] and the low-energy hadron production in e+e^\ensuremath- annihilation. General arguments are given for the calculability of such moments in perturbation theory using both a finite-order analysis and infinite resummation on the contour. Nonperturbative contributions emerging from the operator product expansion for two-point correlators are discussed within explicit models for the physical spectra. The quantitative analysis strongly disfavors weight functions that suppress the high-energy contribution to theoretical moments. This is in agreement with expectations from qualitative considerations in perturbative QCD with asymptotic freedom. We discuss the implication of our results for the ultimate accuracy that can be reached in \ensuremathτ decays and low-energy e+e^\ensuremath- annihilation into hadrons with present experimental data.