# Recent Results on $\tau$ Decays

## TL;DR

This paper reports new experimental results on various tau decay modes from Belle and BABAR, including branching fractions and spectral functions, which are used to refine measurements of the CKM matrix element |V_us|.

## Contribution

It provides updated measurements of tau decay branching fractions and spectral functions, improving the precision of |V_us| determination from tau decays.

## Key findings

- New branching fraction measurements for multiple tau decay modes.
- Determination of the spectral function from K^- K^0_S mass spectrum.
- Refined value of |V_us| from tau decay data.

## Abstract

We present herein new results from Belle on the $\tau^- \rightarrow \pi^- \nu_{\rm \tau} \ell^+ \ell^- $ branching fraction and from BABAR on the $\tau^- \rightarrow K^- (0,1,2,3) \pi^0 \nu_{\rm \tau}$, $\tau^- \rightarrow \pi^- (3,4) \pi^0 \nu_{\rm \tau}$ and $\tau^- \rightarrow K^- K^0_{\rm S} \nu_{\rm \tau}$ branching fractions. From the $K^- K^0_{\rm S}$ mass spectrum we determine the spectral function. The improved branching fraction measurements of the $\tau^- \rightarrow K^- (0,1,2,3) \pi^0 \nu_{\rm \tau}$ decays are used to determine $|V_{\rm us}|$ from $\tau^- \rightarrow X_{\rm s}^- \nu_{\rm \tau}$ inclusive decays.