AN EFFECTIVE LAGRANGIAN CALCULATION OF THE SEMILEPTONIC DECAY MODES OF THE τ LEPTON

Abstract

The semileptonic decay rates of the τ lepton into final states containing up to three pseudoscalar mesons are calculated using a general low energy effective Lagrangian for pseudoscalar and vector mesons with U (3)× U (3) chiral symmetry. Symmetry breaking is taken into account in the meson masses and mixing angles. All of the coupling constants in the Lagrangian are determined empirically from vector meson decay data without additional ad hoc hypotheses such as vector meson dominance. The results compare well with the measured decay rates where data are available. No unexpectedly large branching fractions are found that might account for the “missing” decay modes of the τ.