A short review of the vector charmonium-like state $\psi(4230)$

TL;DR

This review summarizes the experimental and theoretical understanding of the $ ext{psi}(4230)$ charmonium-like state, discussing its possible exotic nature and various models explaining its properties.

Contribution

It provides a comprehensive overview of experimental data and evaluates four main theoretical scenarios for $ ext{psi}(4230)$, highlighting key observables for future research.

Findings

Experimental data on mass, lineshapes, and decay widths are summarized.

Four theoretical models are compared regarding their explanations of $ ext{psi}(4230)$.

Potential exotic partners are identified as crucial for understanding the state.

Abstract

We present a concise review of the vector charmonium state $\psi(4230)$, which was originally labelled as $Y(4260)$ in the literature. As one of the earliest candidates for a QCD exotic states, its interpretation has initiated various ideas about possible manifestations of non-perturbative mechanisms in the charmonium mass regime. In this short article we briefly review the experimental status of $\psi(4230)$ and discuss possible theoretical interpretations. We will focus on four broadly investigated scenarios, i.e. tetraquark, hybrid, hadro-quarkonium, and hadronic molecule, and highlight the key issues based on these approaches. Crucial experimental observables, e.g. mass position, lineshapes, di-lepton decay width $\Gamma_{ee}$, production rates in $B$ meson decays, dominant hadronic decay patterns, and the potential $1^{-+}$ and $0^{--}$ exotic partners, are assessed, which can provide crucial structure information for understanding this mysterious state.