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

TL;DR

This study searches for invisible decay modes of the $B^{0}$ meson using a large data sample at Belle, setting an upper limit on the decay's branching fraction due to no significant signal detection.

Contribution

First search for $B^{0}$ decays into invisible final states at Belle, establishing an upper limit on the branching fraction with a large dataset.

Findings

No significant signal observed for $B^{0}$ to invisible decays.

Upper limit on branching fraction set at $1.3 imes 10^{-4}$.

Method involves reconstructing the other $B$ and checking for no additional particles.

Abstract

We report a search for $B^{0}$ decays into invisible final states using a data sample of $657 \times 10^{6}$ $B\bar{B}$ pairs collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB $e^{+}e^{-}$ collider. The signal is identified by fully reconstructing a hadronic decay of the accompanying $B$ meson and requiring no other particles in the event. No significant signal is observed, and we obtain an upper limit of $1.3 \times 10^{-4}$ at the 90% confidence level for the branching fraction of invisible $B^{0}$ decay.