Search for $Z^{+}_{s1}$ and $Z^{+}_{s2}$ strangeonium-like structures

TL;DR

This paper predicts the masses of two charged strangeonium-like molecular states, $Z^{+}_{s1}$ and $Z^{+}_{s2}$, using QCD sum rules, suggesting experimental searches for these structures.

Contribution

It provides the first QCD sum rule predictions for the masses of $Z^{+}_{s1}$ and $Z^{+}_{s2}$, supporting their potential existence as molecular states.

Findings

Predicted mass of $Z^{+}_{s1}$ is $1.85 ext{ GeV}$

Predicted mass of $Z^{+}_{s2}$ is $2.02 ext{ GeV}$

Both masses are above their respective meson thresholds.

Abstract

Theoretically, it has been presumed from an effective Lagrangian calculation that there could exist two charged strangeonium-like molecular states $Z^{+}_{s1}$ and $Z^{+}_{s2}$, with $K\bar{K}^{*}$ and $K^{*}\bar{K}^{*}$ configurations respectively. In the framework of QCD sum rules, we predict that masses of $Z^{+}_{s1}$ ($K\bar{K}^{*}$) and $Z^{+}_{s2}$ ($K^{*}\bar{K}^{*}$) are $1.85\pm0.14 GeV$ and $2.02\pm0.15 GeV$ respectively, which are both above their respective two meson thresholds. We suggest to put in practice the search for these two charged strangeonium-like structures in future experiments.