Tests for Tau's Charged-Current Structure

Abstract

The Lorentz structure of the tau lepton's charged-current can almost be completely determined by use of stage-two spin-correlation functions for the $\{ρ^{-},ρ^{+}\}$and $\{a_1^{-},a_1^{+}\}$ decay modes. It is possible to test for a ``$(V-A)$ $ + $ something'' structure in the ${J^{Charged}}_{Lepton}$ current, so as to bound the scales $Λ$ for ``new physics" such as arising from tau weak magnetism, weak electricity, and/or 2nd-class currents. In practice, only limited information can be obtained from the $τ\rightarrow πν$ modes.