Analysis of the $Y(4220)$ and $Y(4390)$ as molecular states with QCD sum rules

TL;DR

This paper investigates the nature of the $Y(4220)$ and $Y(4390)$ particles, using QCD sum rules to determine if they can be described as molecular states composed of specific meson pairs.

Contribution

The study provides a detailed QCD sum rule analysis supporting the assignment of $Y(4390)$ as a $Dar{D}_1(1^{--})$ molecular state, while questioning the molecular nature of $Y(4220)$.

Findings

$Y(4390)$ is consistent with being a $Dar{D}_1(1^{--})$ molecular state.

$Y(4220)$ is less likely to be a molecular state based on the calculations.

QCD sum rules effectively distinguish molecular state candidates.

Abstract

In this article, we assign the $Y(4390)$ and $Y(4220)$ to be the vector molecular states $D\bar{D}_1(2420)$ and $D^*\bar{D}_0^*(2400)$, respectively, and study their masses and pole residues with the QCD sum rules in details. The present calculations only favor assigning the $Y(4390)$ to be the $D\bar{D}_1(1^{--})$ molecular state.