Signature of an $h_1$ state in the $J/\psi \to \eta h_1 \to \eta K^{*0}\bar{K}^{*0}$ decay

TL;DR

The paper identifies a new $h_1$ resonance near 1830 MeV in $J/ar{J}$ decays, supported by theoretical modeling and model-independent analysis, indicating a threshold enhancement linked to this state.

Contribution

It demonstrates the existence of an $h_1$ state around 1830 MeV in $J/ar{J}$ decay data using both theoretical and model-independent methods.

Findings

Resonance around 1830 MeV with 110 MeV width identified

Enhancement in $K^* ar{K}^*$ mass spectrum linked to $h_1$ state

Model-independent analysis supports the resonance interpretation

Abstract

The BES data on the $J/\psi \to \eta K^{*0}\bar{K}^{*0}$ reaction show a clear enhancement in the $K^{*0}\bar{K}^{*0}$ mass distribution close to the threshold of this channel. Such an enhancement is usually a signature of a L=0 resonance around threshold, which in this case would correspond to an $h_1$ state with quantum numbers $I^G(J^{PC})=0^-(1^{+-})$. A state around $1800\ \text{MeV}$ results from the interaction of the $K^* \bar{K}^*$ using the local hidden gauge approach. We show that the peak observed in $J/\psi \to \eta K^{*0}\bar{K}^{*0}$ naturally comes from the creation of this $h_1$ state with mass and width around $1830\ \text{MeV}$ and $110\ \text{MeV}$, respectively. A second analysis, model independent, corroborates the first result, confirming the relationship of the enhancement in the invariant mass spectrum with the $h_1$ resonance.