Improved measurements of $D_s$ meson decay constant and branching fractions of $D_s^+\to K^-K^+\pi^+$, $\bar{K}{}^0K^+$ and $\eta\pi^+$ decays from Belle

TL;DR

This paper reports precise measurements of $D_s^+$ meson decay constants and branching fractions for leptonic and hadronic decay modes using Belle data, improving the understanding of charm meson properties.

Contribution

The study provides the most accurate measurements to date of $D_s^+$ decay constants and branching fractions, utilizing a large data sample from Belle at KEKB.

Findings

Measured $D_s^+ o au^+ u_{ au}$ branching fraction as 5.70%

Determined $D_s$ decay constant $ds$ as 255.0 MeV

Obtained new precise branching fractions for hadronic decays

Abstract

We present preliminary absolute branching fraction measurements of leptonic $D_s^+$ decays to $\mu^+\nu_{\mu}$ and $\tau^+\nu_{\tau}$, and of hadronic $D_s^+$ decays to $K^-K^+\pi^+$, $\bar{K}{}^0K^+$ and $\eta\pi^+$. The results are obtained from a large data sample collected near the $\Upsilon(4S)$ and $\Upsilon(5S)$ resonances with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. We obtain the the branching fractions ${\cal B}(D_s^+\to\mu^+\nu_{\mu})=(0.528\pm0.028\pm0.019)%$ and ${\cal B}(D_s^+\to\tau^+\nu_{\tau})=(5.70\pm0.21{}^{+0.31}_{-0.30})%$ which are combined to determine the $D_s$ decay constant $\fds=(255.0\pm4.2\pm5.0)$ MeV, where the first and second uncertainties are statistical and systematic, respectively. Branching fractions of hadronic decays are measured to be ${\cal B}(D_s^+\to K^-K^+\pi^+)=(5.06 \pm 0.15\pm 0.19)%$, ${\cal B}(D_s^+\to\bar{K}{}^0K^+)=(2.84 \pm 0.12\pm 0.08)%$ and ${\cal B}(D_s^+\to\eta\pi^+)=(1.79\pm0.14\pm 0.05)%$.