Pseudoscalar production at omega omega threshold in J/psi -> gamma omega omega

TL;DR

This study investigates the pseudoscalar resonance near the omega omega threshold in J/psi decays, identifying a new state with specific mass, width, and decay properties through partial wave analysis.

Contribution

It provides the first detailed analysis of the pseudoscalar structure in J/psi->gamma omega omega decays, including mass, width, and branching fraction measurements.

Findings

Identified a pseudoscalar resonance at 1744 MeV/c^2

Measured the resonance width as approximately 244 MeV/c^2

Determined the product branching fraction as about 2 x 10^{-3}

Abstract

The decay channel J/\psi->gamma omega omega, omega -> pi+ pi- pi0 is analyzed using a sample of 5.8x10^7 J/psi events collected with the BESII detector. The omega omega invariant mass distribution peaks at 1.76 GeV/c^2, just above the omega omega threshold. Analysis of angular correlations indicate that the omega omega system below 2 GeV/c^2 is predominantly pseudoscalar. A partial wave analysis confirms the predominant pseudoscalar structure, together with small 0^{++} and 2^{++} contributions, and yields a pseudoscalar mass M = 1744 \pm 10 (stat) \pm 15 (syst) MeV/c^2, a width Gamma = 244^{+24}_{-21} (stat) \pm 25 (syst) MeV/c^2, and a product branching fraction Br(J/psi-> gamma eta(1760)) \cdot Br(\eta(1760)->omega omega) = (1.98 \pm 0.08 (stat) \pm 0.32 (syst)) x 10^{-3}.