Sensitivities of one-prong tau branching fractions to tau neutrino mass, mixing, and anomalous charged current couplings

TL;DR

This paper investigates how various tau decay properties and couplings are sensitive to new physics parameters like neutrino mass, mixing, and anomalous couplings, using current and future experimental data.

Contribution

It provides a comprehensive analysis of tau decay sensitivities to new physics parameters and estimates future experimental constraints.

Findings

Current data constrains tau neutrino mass and mixing.

Future measurements could tighten bounds on anomalous couplings.

Constraints inform models of tau compositeness and Higgs sectors.

Abstract

We analyse the sensitivities of exclusive one-prong tau branching fractions to: the tau neutrino mass; its mixing with a fourth generation neutrino; the weak charged current magnetic and electric dipole moments of the tau; and the Michel parameter $\eta$. Quantitative constraints are derived from current experimental data and the future constraints derivable from tau-charm factory measurements are estimated. The anomalous coupling constraints are used to constrain the tau compositeness scale and the allowed parameter space for Higgs doublet models.