A novel explanation of charmonium-like structure in $e^+e^-\to \psi(2S)\pi^+\pi^-$

TL;DR

This paper proposes a non-resonant interference explanation for the charmonium-like structure $Y(4360)$ observed in $e^+e^- o \psi(2S)\pi^+\pi^-$, suggesting it is not a genuine resonance but an effect of production amplitude interference.

Contribution

It introduces a non-resonant interference model to explain the $Y(4360)$ structure, challenging the resonance interpretation and aligning with its selective decay observations.

Findings

$Y(4360)$ is explained as an interference effect, not a true resonance.

The model accounts for the absence of $Y(4360)$ in open-charm channels.

The explanation aligns with the experimental decay channel observations.

Abstract

We first present a non-resonant description to charmonium-like structure $Y(4360)$ in the $\psi(2S)\pi^+\pi^-$ invariant mass spectrum of the $e^+e^-\to \psi(2S)\pi^+\pi^-$ process. The $Y(4360)$ structure is depicted well by the interference effect of the production amplitudes of $e^{+} e^{-} \to \psi(2S) \pi^+ \pi^-$ via the intermediate charmonia $\psi(4160)/\psi(4415)$ and direct $e^+e^-$ annihilation into $\psi(2S)\pi^+ \pi^-$. This fact shows that $Y(4360)$ is not a genuine resonance, which naturally explains why $Y(4360)$ was only reported in its hidden-charm decay channel $\psi(2S)\pi^+\pi^-$ and was not observed in the exclusive open-charm decay channel or $R$-value scan.