Tau Physics

TL;DR

Tau physics provides a unique testing ground for the weak interaction, lepton universality, and potential new physics, utilizing leptonic and semileptonic tau decays to explore fundamental particle interactions and low-energy strong effects.

Contribution

This paper summarizes the current experimental and theoretical understanding of tau decays, highlighting their role in testing the Standard Model and searching for new physics phenomena.

Findings

Tau decays test weak current structure and lepton universality.

Hadronic tau decays probe low-energy strong interactions.

Tau decays can reveal new physics like neutrino mass or conservation law violations.

Abstract

The pure leptonic or semileptonic character of tau decays makes them a good laboratory to test the structure of the weak currents and the universality of their couplings to the gauge bosons. The hadronic $\tau$ decay modes constitute an ideal tool for studying low--energy effects of the strong interactions in very clean conditions. New physics phenomena, such as a non-zero $m_{\nu_\tau}$ or violations of conservation laws can also be searched for with tau decays. The present experimental and theoretical status of tau physics is summarized.