Distinguishing cusp effects and near-threshold-pole effects

Abstract

We make use of a unitarized coupled-channel model to analyze the mass distribution data of final states in production processes of $X(4260)$. By analyzing the analytical structures of the decay amplitudes, we find that the line shape of $Z_c(3900)$ signal is related to the combined effect of a pair of near-threshold "shadow" poles and the $(D{\bar{D}}^{\ast }{)}^{\pm }$ thresholds, in which the third-sheet pole might provide a dominant contribution. As all the coupled channels effects are tuning off, the trajectories of these two poles suggest that the $Z_c(3900)$ might originate from the attractive interaction of $(D^{\ast }{\bar{D}}^{\ast }{)}^{\pm }$ through a long-distance interaction, $e.g.$ $\pi$-exchange interaction, as a "deuteron-like" state. There is no nearby pole structure corresponding to the $Z_c(4025)$ signal in the $(D^{\ast }{\bar{D}}^{\ast }{)}^{\pm }$ mass distribution.

10 pages, 3 figures

References in corpus (5)

• Heavy quarkonium: progress, puzzles, and opportunities
• $Z_b$ and $Z_c$ Exotic States as Coupled Channel Cusps
• Could the near-threshold $XYZ$ states be simply kinematic effects?
• $Z_c(3900)$ as a resonance from the $D{\bar{D}}^{\ast }$ interaction
• The origin of light $0^{+}$ scalar resonances

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• $Z_c(3900)/Z_c(3885)$ as a virtual state from $\pi J/\psi -{\bar{D}}^{\ast }D$ interaction
• $Z_c(3900)$: Confronting theory and lattice simulations
• On Friedrichs Model with Two Continuum States
• Partial Wave Decomposition in Friedrichs Model With Self-interacting Continua
• XYZ States: Theory Overview
• Charmoniumlike Channels $1^{+}$ with Isospin $1$ from Lattice and Effective Field Theory
• Investigation of the $X(4020)$ peak in the $D^{\ast }{\bar{D}}^{\ast }$ and $\pi h_c$ channels
• Photon-induced production of the exotic charged charmonium-like state $Z_c(3900)$ off nuclear targets and its internal structure