CLEO Results on Tau Michel Parameters

TL;DR

This paper reports precise measurements of tau Michel Parameters from CLEO data, providing new limits on theoretical models like the MSSM and left-right W models, with three different analysis methods.

Contribution

It introduces three novel analyses of tau decay data to measure Michel Parameters with higher precision than previous results.

Findings

More precise Michel Parameter measurements than PDG averages.

Limits set on charged Higgs mass in MSSM.

Constraints on right-handed W bosons in left-right models.

Abstract

We present measurements of the tau Michel Parameters made by the CLEO experiment. Three different analyses are performed: a spin-independent lepton spectrum analysis and a second spin-dependent analysis using $\ell^\pm$ \vs\ $\pi^\mp\pi^0$ events, and a third spin-dependent analysis using $\pi^+$ \vs\ $\pi^-$ events. the results are used to derive limits on the general four-fermion couplings, the mass of the charged Higgs in the MSSM, and a right-handed $W$ in left-right models. Many of these measurements are more precise than the PDG world averages.