Search for $D^{0}$ decays to invisible final states at Belle

TL;DR

This paper reports the first search for $D^0$ meson decays into invisible final states using a large data sample from the Belle experiment, setting an upper limit on the branching fraction.

Contribution

It introduces the first experimental search for $D^0$ to invisible decays and establishes an upper limit on its branching fraction.

Findings

No significant signal observed for $D^0$ to invisible decays.

Upper limit on the branching fraction is set at $9.4 imes 10^{-5}$.

Analysis uses a large 924 fb$^{-1}$ data sample from Belle.

Abstract

We report the result from the first search for $D^0$ decays to invisible final states. The analysis is performed on a data sample of 924 $\rm{fb}^{-1}$ collected at and near the $\Upsilon(4S)$ and $\Upsilon(5S)$ resonances with the Belle detector at the KEKB asymmetric-energy $e^{+}e^{-}$ collider. The absolute branching fraction is determined using an inclusive $D^0$ sample, obtained by fully reconstructing the rest of the particle system including the other charmed particle. No significant signal yield is observed and an upper limit of $9.4\times 10^{-5}$ is set on the branching fraction of $D^0$ to invisible final states at 90\% confidence level.