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

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 $T\ne 0$. 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.

Comments: 11 pages, 4 figures