Impact of a thermal medium on newly observed $Z_{cs}(3985)$ resonance and its $ b $-partner

TL;DR

This paper investigates how a hot medium affects the properties of the recently observed $Z_{cs}(3985)$ resonance and its bottom partner, providing insights into QCD phase transitions and hot-dense matter.

Contribution

It offers the first finite-temperature QCD sum rule analysis of the $Z_{cs}(3985)$ and its bottom partner, including non-perturbative effects up to sixth order.

Findings

Thermal mass and coupling constants decrease with temperature.

Properties of $Z_{cs}(3985)$ are significantly modified in hot medium.

Estimates of bottom partner parameters at finite temperature.

Abstract

Motivated by the very recent discovery of the strange hidden-charm exotic state $Z_{cs}(3985)$ by the BESIII Collaboration, we study possible interpretation of this exotic state both at $ T= 0 $ and $ T\neq 0 $. We analytically compute the mass and meson-current coupling constant of this resonance with spin-parity $ J^{PC} = 1^{+-}$ at finite temperature approximation up to sixth order of the thermal operator dimension including non-perturbative contributions. Extracting thermal mass and meson-current coupling constant sum rules, the modifications on properties of $Z_{cs}(3985)$ state in hot medium is determined. As a by product, the hadronic parameters of the bottom partner of $Z_{cs}(3985)$ is estimated as well. Moreover the search of temperature effects on the hadronic parameters of hidden-charm meson $Z_{cs}(3985)$ and the bottom partner make us understand the phase transitions, chiral symmetry breaking and the properties of hot-dense matter in QCD.