Structure Functions and Distributions in Semileptonic Tau Decays

Abstract

Semileptonic decays of polarized $τ$ leptons are investigated. The most general angular distribution of three meson final states ($τ\rightarrow ππν,\,Kπν,\, πππν,\\ \,Kππν,\, KKπν,\, KKKν,\, ηππν,\,\ldots{}$) is discussed. It is shown, that the most general distribution can be characterized by 16 structure functions, most of which can be determined in currently ongoing high statistics experiments. Emphasis is put on $τ$ decays in $e^{+}e^{-}$ experiments where the neutrino escapes detection and the $τ$ rest frame cannot be reconstructed. The structure of the hadronic matrix elements, based on CVC and chiral lagrangians, is discussed.