Precise measurement of hadronic $\tau$-decays in modes with $\eta$ mesons

TL;DR

This paper reports precise measurements of branching fractions for specific hadronic tau decays involving eta mesons, significantly improving the accuracy over previous results using data from the Belle detector at KEKB.

Contribution

The study provides the most accurate measurements to date of tau decay modes with eta mesons, enhancing understanding of hadronic tau decays and testing theoretical models.

Findings

Measured branching fractions with improved precision

Reduced uncertainties by factors of 4 to 8

Enhanced understanding of tau decay dynamics

Abstract

We have measured branching fractions of hadronic $\tau$ decays involving an $\eta$ meson using 485 fb^{-1} of data collected with the Belle detector at the KEKB asymmetric-energy e^+e^- collider. We obtain the following branching fractions: ${\cal B}(\tau^-\to K^- \eta \nu_{\tau})=(1.62\pm 0.05 \pm 0.09)\times 10^{-4}$, ${\cal B}(\tau^-\to K^- \pi^0 \eta \nu_{\tau}) =(4.7\pm 1.1 \pm 0.4)\times 10^{-5}$, ${\cal B}(\tau^-\to \pi^- \pi^0 \eta \nu_{\tau})=(1.39 \pm 0.03 \pm 0.07) \times 10^{-3}$, and ${\cal B}(\tau^-\to K^{*-} \eta \nu_{\tau})=(1.13\pm 0.19 \pm 0.07)\times 10^{-4}$ improving the accuracy compared to the best previous measurements by factors of six, eight, four and four, respectively.