Decoding the nature of $Z_{cs}(3985)$ and establishing the spectrum of charged heavy quarkoniumlike states in chiral effective field theory

Abstract

We study the newly observed charmoniumlike state $Z_{cs}(3985)$ in the framework of chiral effective field theory. The interaction kernel of the ${\bar{D}}_s{D}^{\ast }/{\bar{D}}_s^{\ast }D$ system is calculated up to the next-to-leading order with the explicit chiral dynamics. With the fitted parameters extracted from the $Z_c(3900)$ data as inputs, the mass, width and event distributions of the $Z_{cs}(3985)$ are very consistent with the experimental measurements. Our studies strongly support the $Z_{cs}(3985)$ as the partner of the $Z_c(3900)$ in the SU(3)${}_f$ symmetry and the ${\bar{D}}_s{D}^{\ast }/{\bar{D}}_s^{\ast }D$ molecular resonance with the same dynamical origin as the other charged heavy quarkoniumlike states. We precisely predict the resonance parameters of the unobserved states in ${\bar{D}}_s^{\ast }{D}^{\ast }$, $B_s^{\ast }\bar{B}/B_s{\bar{B}}^{\ast }$ and $B_s^{\ast }{\bar{B}}^{\ast }$ systems, and establish a complete spectrum of the charged charmoniumlike and bottomoniumlike states with the $I(J^P)$ quantum numbers $1(1^{+})$ and $\frac{1}{2}(1^{+})$, respectively.

Comments: 5 pages, 3 figures and 1 table