The strange cousin of the $Z_c(4020/4025)$ as tetraquark state

TL;DR

This paper investigates the nature of the $Z_c(4020/4025)$ as an $Aar{A}$-type hidden-charm tetraquark state using QCD sum rules, providing theoretical support for its tetraquark assignment and predicting properties of its strange partner.

Contribution

The study introduces a consistent QCD sum rule analysis of $Aar{A}$-type tetraquark states, including decay widths and strange counterparts, advancing understanding of exotic hadron structures.

Findings

Supports $Z_c(4020/4025)$ as an $Aar{A}$-type tetraquark with $J^{PC}=1^{+-}$

Predicts decay widths consistent with experimental data for non-strange states

Provides theoretical predictions for strange partner states for future experimental tests

Abstract

Motivated by the analogous properties of the $Z_c(3900/3885)$ and $Z_{cs}(3985/4000)$, we tentatively assign the $Z_c(4020/4025)$ as the $A\bar{A}$-type hidden-charm tetraquark state with the $J^{PC}=1^{+-}$, where the $A$ denotes the axialvector diquark states, and explore the $A\bar{A}$-type tetraquark states without strange, with strange and with hidden-strange via the QCD sum rules in a consistent way. Then we explore the hadronic coupling constants in the two-body strong decays of the tetraquark states without strange and with strange via the QCD sum rules based on rigorous quark-hadron duality, and acquire the partial decay widths and total decay widths. The present calculations support assigning the $Z_c(4020/4025)$ as the $A\bar{A}$-type tetraquark state with the $J^{PC}=1^{+-}$, while the predictions for its strange cousin $Z_{cs}$ state can be confronted to the experimental data in the future.