Sigma_c Dbar and Lambda_c Dbar states in a chiral quark model

TL;DR

This paper investigates Sigma_c Dbar and Lambda_c Dbar states using a chiral quark model, finding a bound state for Sigma_c Dbar due to attractive interaction, while Lambda_c Dbar remains unbound.

Contribution

It provides the first detailed analysis of Sigma_c Dbar and Lambda_c Dbar interactions within a chiral quark model using the RGM approach, highlighting the conditions for bound state formation.

Findings

Sigma_c Dbar interaction is attractive, leading to a bound state.

Lambda_c Dbar interaction is repulsive, no bound state.

Channel coupling effects are negligible due to large threshold gap.

Abstract

The S-wave Sigma_c Dbar and Lambda_c Dbar states with isospin I=1/2 and spin S=1/2 are dynamically investigated within the framework of a chiral constituent quark model by solving a resonating group method (RGM) equation. The results show that the interaction between Sigma_c and Dbar is attractive, which consequently results in a Sigma_c Dbar bound state with the binding energy of about 5-42 MeV, unlike the case of Lambda_c Dbar state, which has a repulsive interaction and thus is unbound. The channel coupling effect of Sigma_c Dbar and Lambda_c Dbar is found to be negligible due to the fact that the gap between the Sigma_c Dbar and Lambda_c Dbar thresholds is relatively large and the Sigma_c Dbar and Lambda_c Dbar transition interaction is weak.