Search for invisible decays of $\omega$ and $\phi$ with $J/\psi$ data at BESIII

TL;DR

This study searches for invisible decays of the $ ho$ and $ ho$ mesons using $J/ ext{psi}$ data, setting upper limits on their branching fractions and providing constraints relevant to new physics models involving dark matter.

Contribution

First experimental search for invisible decays of light vector mesons $ ho$ and $ ho$ via $J/ ext{psi}$ decays, establishing upper limits on their branching fractions.

Findings

No significant signal observed for invisible decays.

Upper limits on branching ratios are set at $7.3 imes 10^{-5}$ for $ ho$ and $1.7 imes 10^{-4}$ for $ ho$.

Constraints on new physics models involving dark matter are improved.

Abstract

Using a data sample of $(1310.6 \pm 7.0)\times 10^6$ $J/\psi$ events collected with the BESIII detector operating at the BEPCII collider, we perform the first experimental search for invisible decays of a light vector meson ($V=\omega,\phi$) via $J/\psi \to V \eta$ decays. The decay of $\eta \to \pi^+\pi^-\pi^0$ is utilized to tag the $V$ meson decaying into the invisible final state. No evidence for a significant invisible signal is observed, and the upper limits on the ratio of branching fractions at the 90\% confidence level are determined to be $\frac{\mathcal{B}(\omega \rightarrow \rm{invisible})}{\mathcal{B}(\omega \to \pi^+\pi^-\pi^0)} < 8.1 \times 10^{-5}$ and $\frac{\mathcal{B}(\phi \to \rm{invisible})}{\mathcal{B}(\phi \to K^+K^-)} < 3.4\times 10^{-4}$. By using the world average values of $\mathcal{B}(\omega \to \pi^+\pi^-\pi^0)$ and $\mathcal{B}(\phi\to K^+K^-)$, the upper limits on the decay branching fractions at the $90\%$ confidence level are set as $\mathcal{B}(\omega \to \rm{invisible})< 7.3 \times 10^{-5}$ and $\mathcal{B}(\phi \to \rm{invisible})< 1.7\times 10^{-4}$, respectively.