Properties of single cluster structure of $d^*(2380)$ in chiral SU(3) quark model

TL;DR

This study investigates the structure of the $d^*(2380)$ resonance using a chiral SU(3) quark model, calculating its mass, width, and size, and suggesting it is a six-quark exotic state with specific decay modes.

Contribution

It provides a detailed single-cluster analysis of $d^*(2380)$ within the chiral SU(3) quark model, offering new insights into its structure and decay characteristics.

Findings

Mass and width are about 2394 MeV and 25 MeV, respectively.

The stable size is approximately 0.75 fm.

The $d^*$ is likely a six-quark dominated exotic state with a spherical shape.

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 scattering and binding behaviors of baryonic systems. The mass and width are explicitly calculated with two types of trial wave functions. The result shows that the $(0s)^6 [6]_{orb}$ configuration is easy to convert to the configuration with the same $[6]_{orb}$ symmetry but $2\hbar \omega$ excitation back and forth, however, it is seldom to turn into a two-cluster configuration with a (1s) relative motion in between. The resultant mass and width are about $2394$MeV and $25$MeV, respectively, and the stable size is about $0.75fm$, which are consistent with both the results in the two-cluster configuration calculation and the data measured by the COSY collaboration. It seems that the observed $d^*$ is a six-quark dominated exotic state with a spherical shape and breath mode in the coordinate space. Moreover, if $d^*$ does have $2\hbar \omega$ excitation, the $d^* \to np\pi\pi\pi$ decay mode might be a good place to distinguish the real structure of the observed phenomenon by COSY. The masses of various isospin-spin states of six-light-quark systems are also computed. It is shown that by considering the coupling with the configurations with $2\hbar \omega$ excitations, only the mirror state with $IS$=$30$ will be lower down to the place where whose mass is slightly higher than the value of the $\Delta\Delta$ threshold.