1996/04/10 by G. Colangelo, Gilberto Colangelo, Markus Finkemeier +3 · 2 citations
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.54.4403
published as Phys.Rev. D54 (1996) 4403-4418 · 39 pages, Latex, including 8 Postscript figures. The complete paper is also available via anonymous ftp at ftp://www-ttp.physik.uni-karlsruhe.de/ , or via www at http://www-ttp.physik.uni-karlsruhe.de/cgi-bin/preprints
arxiv created 1996/04/10 · openalex publication_date 1996/10/01 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
In a small window of phase space, chiral perturbation theory can be used to make standard model predictions for \ensuremathτ decays into two and three pions. For \ensuremathτ\ensuremath→2\ensuremathπ\ensuremathν_\ensuremathτ, we give the analytical result for the relevant form factor FV up to two loops, then calculate the differential spectrum and compare with available data. For \ensuremathτ\ensuremath→3\ensuremathπ\ensuremathν_\ensuremathτ, we have calculated the hadronic matrix element to one loop. We discuss the decomposition of the three pion states into partition states and we give detailed predictions for the decay in terms of structure functions. We also compare with low energy predictions of meson dominance models. Overall, we find good agreement, but also some interesting discrepancies, which might have consequences beyond the limit of validity of chiral perturbation theory.