Study of J/Psi decays into eta Kstar Kstar-bar

TL;DR

This paper reports the first observation of the decay J/psi to eta K* K*bar, measuring its branching fraction, and searches for a resonance Y in this decay mode, setting an upper limit due to no observed signal.

Contribution

First observation of J/psi to eta K* K*bar decay and setting an upper limit on Y resonance production in this channel.

Findings

Branching fraction of J/psi to eta K* K*bar is (1.15 ± 0.13 ± 0.22)×10^{-3}.

No evidence of Y resonance in J/psi to eta Y, Y to K* K*bar decay.

Upper limit on the product of branching fractions for Y resonance is 2.52×10^{-4} at 90% CL.

Abstract

We report the first observation of $\mPJpsi \to \mPeta\mPKst\mAPKst$ decay in a $\mPJpsi$ sample of 58 million events collected with the BESII detector. The branching fraction is determined to be $(1.15 \pm 0.13 \pm 0.22)\times 10^{-3}$. The selected signal event sample is further used to search for the $\mPY$ resonance through $\mPJpsi \to \mPeta \mPY, \mPY\to\mPKst\mAPKst$. No evidence of a signal is seen. An upper limit of \mathrm{Br}(\mPJpsi \to \mPeta \mPY)\cdot\mathrm{Br}(\mPY\to\mPKst\mAPKst) < 2.52\times 10^{-4} is set at the 90% confidence level.