$Y(4626)$ in a chiral constituent quark model

TL;DR

This study investigates the $car{s}sar{c}$ tetraquark system using a chiral constituent quark model, finding possible resonance states that could correspond to the experimental $Y(4620)$, but no bound states are formed.

Contribution

It is the first to analyze the $Y(4620)$ candidate within a chiral constituent quark model considering multiple configurations and resonance states.

Findings

Several resonance states identified with energies close to 4620 MeV.

No bound tetraquark states found in the model.

Resonance at 4531 MeV could be the $Y(4620)$ candidate.

Abstract

Recently, Belle Collaboration reported a new exotic state $Y(4620)$ with mass at 4625.9 MeV in the positronium annihilation process. Inspired by experiment, we study the tetraquark system $c\bar{s}s\bar{c}$ with quantum numbers $J^{P}=1^{-}$ in the framework of chiral constituent quark model with the help of Gaussian expansion method. Two structures, diquark-antidiquark and meson-meson, with all possible color and spin configurations are considered. The result shows that no bound state can be formed. To investigate the possible resonance states, the real scaling method is employed. Several resonance states with energies 4354, 4408, 4469, 4497 and 4531 MeV, are proposed. Taking into account the errors in calculating the $q\bar{q}$ mesons, the system errors in the calculation of four-quark system are around 60$\sim 100$ MeV. The resonance with energy 4531 MeV is possible the candidate of the newly found state $Y(4620)$.