Improved measurements of branching fractions for $\eta_c\to\phi\phi$ and $\omega\phi$

TL;DR

This paper reports precise measurements of the branching fraction for $ o o o$ decay and sets an upper limit for the suppressed decay mode using a large dataset from BESIII, improving understanding of $ o$ decay dynamics.

Contribution

The study provides the first precise measurement of $ o o$ branching fraction and establishes a new upper limit for the $ o o$ decay, refining previous experimental constraints.

Findings

$ o o$ branching fraction measured as $(2.5 extpm0.3^{+0.3}_{-0.7} extpm0.6) imes10^{-3}$

No significant signal for $ o o$ decay observed

Upper limit for $ o o$ decay set at $2.5 imes10^{-4}$ at 90",

Abstract

Using $(223.7\pm1.4)\times10^6$ J/$\psi$ events accumulated with the BESIII detector, we study $\eta_c$ decays to $\phi\phi$ and $\omega\phi$ final states. The branching fraction of $\eta_c\to\phi\phi$ is measured to be $Br(\eta_c\to\phi\phi)=(2.5\pm0.3^{+0.3}_{-0.7}\pm0.6)\times10^{-3}$, where the first uncertainty is statistical, the second is systematic, and the third is from the uncertainty of $Br(J/\psi\to\gamma\eta_c)$. No significant signal for the double OZI-suppressed decay of $\eta_c\to\omega\phi$ is observed, and the upper limit on the branching fraction is determined to be $Br(\eta_c\to\omega\phi)<2.5\times 10^{-4}$ at the 90\% confidence level.