# New charged resonance $Z_{c}^{-}(4100)$: the spectroscopic parameters and width

## TL;DR

This paper investigates the properties of the newly observed charged resonance $Z_{c}^{-}(4100)$ by calculating its mass, coupling constants, and decay widths using QCD sum rules, and finds results consistent with experimental data.

## Contribution

It provides the first detailed QCD sum rule analysis of the $Z_{c}^{-}(4100)$ resonance's spectroscopic parameters and decay channels, offering theoretical support for its observed properties.

## Key findings

- Mass $m=(4080 \,\pm\, 150)$ MeV agrees with LHCb data.
- Total width $\,\Gamma=(147 \,\pm\, 19)$ MeV matches experimental measurements.
- Computed strong couplings for various decay channels support the resonance's structure.

## Abstract

The mass, coupling and width of the newly observed charged resonance $ Z_{c}^{-}(4100)$ are calculated by treating it as a scalar four-quark system with a diquark-antidiquark structure. The mass and coupling of the state $ Z_{c}^{-}(4100)$ are calculated using the QCD two-point sum rules. In these calculations we take into account contributions of the quark, gluon and mixed condensates up to dimension ten. The spectroscopic parameters of $ Z_{c}^{-}(4100)$ obtained by this way are employed to study its $S$-wave decays to $\eta_c(1S)\pi^{-}$, $\eta_c(2S)\pi^{-}$, $D^{0}D^{-}$, and $ J/\psi \rho ^{-}$ final states. To this end, we evaluate the strong coupling constants corresponding to the vertices $Z_{c}\eta_c(1S)\pi^{-}$, $ Z_{c}\eta_c(2S)\pi^{-}$, $Z_{c}D^{0}D^{-}$, and $Z_{c}J/\psi \rho^{-}$ respectively. The couplings $g_{Z_c\eta_{c1} \pi}$, $g_{Z_{c}\eta_{c2} \pi}$ , and $g_{Z_{c}DD}$ are computed by means of the QCD three-point sum rule method, whereas $g_{Z_{c}J/\psi \rho }$ is obtained from the QCD light-cone sum rule approach and soft-meson approximation. Our results for the mass $ m=(4080 \pm 150)~\mathrm{MeV}$ and total width $\Gamma =(147 \pm 19)~\mathrm{ MeV}$ of the resonance $Z_{c}^{-}(4100)$ are in excellent agreement with the existing LHCb data.