Search for Charmonium(-like) states decaying into the $\Omega^-\bar\Omega^+$ final states

TL;DR

This paper reports a search for charmonium-like states decaying into the $\Omega^-ar\Omega^+$ final states using BESIII and CLEO-c data, finding no significant signals but setting new upper limits on branching fractions.

Contribution

First measurement of $\Omega^-ar\\Omega^+$ decay branching fractions for several charmonium states, providing constraints and challenging existing theoretical predictions.

Findings

No significant charmonium(-like) signals observed.

Upper limits set on branching fractions at 90",

Branching fractions are an order of magnitude larger than theoretical expectations.

Abstract

Recently, the BESIII experiment performed a measurement of the energy-dependent Born cross section and the effective form factor for the $e^+e^-\to\Omega^-\bar\Omega^+$ reaction at center-of-mass energies ranging from 3.4 to 4.7 GeV. A fit to the energy dependence of the dressed cross section is performed. With the assumption of a charmonium (like) resonance [i.e., $\psi(3770)$, $\psi(4040)$, $\psi(4160)$, $Y(4230)$, $Y(4360)$, $\psi(4415)$, or $Y(4660)$] plus a power-law function, the fit is applied to the data from the recent BESIII measurement, which was additionally combined with previous CLEO-c measurement data. No significance is found. The products of the branching fraction and the two electronic partial widths for the assumed charmonium(-like) states decaying into the $\Omega^-\bar\Omega^+$ final states are also provided. In addition, by taking the world average values of the electronic branching fraction, the branching fractions for $\psi(3770)$, $\psi(4040)$, $\psi(4160)$, $\psi(4415)$ decaying into $\Omega^-\bar\Omega^+$ final states at the 90\% confidence level are determined for the first time. These are found to be at least an order of magnitude larger than expected from predictions using a scaling based on the observed electronic widths.