# Six-quark structure of $d^*(2380)$ in chiral constituent quark model

## TL;DR

This paper investigates the structure of the $d^*(2380)$ resonance as a six-quark bound state using the chiral SU(3) quark model and variational methods, finding results consistent with experimental data and supporting its hexaquark nature.

## Contribution

The study applies a single cluster model with chiral interactions and variational techniques to analyze $d^*(2380)$, providing new insights into its mass and structure as a hexaquark state.

## Key findings

- Mass of $d^*(2380)$ is about 2356 MeV, aligning with experimental data.
- Medium-range chiral interactions significantly lower the system's mass.
- $d^*(2380)$ is supported as a six-quark bound state near the $eltaelta$ threshold.

## Abstract

The structure of $d^*(2380)$ is re-studied with the single cluster structure in the chiral SU(3) quark model which has successfully been employed to explain the $N-N$ scattering data and the binding energy of deuteron. The binding behavior of such a six quark system is solved by using a variational method. The trial wave function is chosen to be a combination of a basic spherical symmetric component of $[(0s)^6]_{orb}$ in the orbital space with $0\hbar\omega$ excitation and an inner structural deformation component of $[(0s)^5(1s)]_{orb}$ and $[(0s)^4(0p)^2]_{orb}$ in the orbital space with $2\hbar\omega$ excitation, both of which are in the spatial [6] symmetry. It is shown that the mass of the system is about $2356$ MeV, which is qualitative consistent with the result both from the two-cluster configuration calculation and from the data measured by the WASA Collaborations. This result tells us that as long as the medium-range interaction due to the chiral symmetry consideration is properly introduced, the mass of system will be reduced in a rather large extent. It also implies that the observed $d^*$ is a six-quark bound state with respect to the $\Delta\Delta$ threshold, which again supports the conclusion that $d^*$ is a hexaquark dominant state.