Cusps and Exotic Charmonia

TL;DR

This paper presents a simple, causal, and analytic rescattering model that accurately describes exotic charmonium-like resonances $Z_c(3900)$ and $Z_c(4025)$ without requiring poles in the scattering matrix.

Contribution

The paper introduces a novel rescattering model that explains exotic resonances without invoking poles, offering a new perspective on their nature.

Findings

Model accurately fits experimental data

No poles needed in the scattering matrix

Provides a causal and analytic description

Abstract

A simple, causal, and analytic model of final state rescattering is used to describe all available data on the exotic resonances $Z_c(3900)$ and $Z_c(4025)$. The model provides a compelling and accurate representation of experiment with no need for poles in the scattering matrix.