Measurement of the spectral function for the $\tau^-\to K^-K_S\nu_{\tau}$ decay in BABAR experiment

TL;DR

This paper reports a precise measurement of the spectral function and branching fraction for the decay tau- to K- K_S nu_tau using a large dataset from the BABAR experiment, confirming previous results.

Contribution

The study provides the first detailed spectral function measurement for tau- to K- K_S nu_tau decay with high statistical precision.

Findings

Measured branching fraction: (0.739 ± 0.011 (stat) ± 0.020 (syst)) × 10^{-3}

Mass spectrum of the K- K_S system obtained

Results agree with earlier measurements

Abstract

The decay $\tau^{-}\to K^{-}K_S\nu_{\tau}$ has been studied using $430\times10^6$ $e^+e^-\to \tau^+\tau^-$ events produced at a center-of-mass energy around 10.6 GeV at the PEP-II collider and studied with the BABAR detector. The mass spectrum of the $K^{-}K_S$ system has been measured and the spectral function has been obtained. The measured branching fraction ${\cal B}(\tau^{-}\to K^{-}K_S\nu_{\tau}) = (0.739\pm 0.011(\rm stat.)\pm 0.020(\rm syst.))\times 10^{-3}$ is found to be in agreement with earlier measurements.