Understanding the newly observed Y(4008) by Belle

TL;DR

This paper discusses possible interpretations of the newly observed Y(4008) enhancement by Belle, exploring its potential as a $ ext{ψ}(3S)$ state or a $D^*ar{D}^*$ molecular state, and suggests experimental searches to distinguish these hypotheses.

Contribution

It proposes specific decay channels and experimental measurements to identify the nature of Y(4008), advancing understanding of this new resonance.

Findings

Y(4008) can decay into $J/\psi\pi^0\pi^0$ with similar branching ratio as $J/\psi\pi^+\pi^-$

Suggested experimental searches for $D\bar{D}$, $D\bar{D}^*+h.c.$, and multi-pion channels

Different decay patterns can distinguish between $ ext{ψ}(3S)$ and molecular state interpretations

Abstract

Very recently a new enhancement around 4.05 GeV was observed by Belle experiment. In this short note, we discuss some possible assignments for this enhancement, i.e. $\psi(3S)$ and $D^*\bar{D}^*$ molecular state. In these two assignments, Y(4008) can decay into $J/\psi\pi^0\pi^0$ with comparable branching ratio with that of $Y(4008)\to J/\psi\pi^+\pi^-$. Thus one suggests high energy experimentalists to look for Y(4008) in $J/\psi\pi^0\pi^0$ channel. Furthermore one proposes further experiments to search missing channel $D\bar{D}$, $D\bar{D}^*+h.c.$ and especially $\chi_{cJ}\pi^+\pi^-\pi^0$ and $\eta_c\pi^+\pi^-\pi^0$, which will be helpful to distinguish $\psi(3S)$ and $D^*\bar{D}^*$ molecular state assignments for this new enhancement.