Antikaon-nucleon interaction and Lambda(1405) in chiral SU(3) dynamics

TL;DR

This paper uses chiral SU(3) dynamics to accurately describe the antikaon-nucleon interaction and the Lambda(1405) resonance, revealing its dominant molecular structure and providing insights for strangeness nuclear physics.

Contribution

It offers a quantitative chiral SU(3) framework for the antikaon-nucleon interaction, incorporating recent experimental data and analyzing the Lambda(1405)'s internal structure.

Findings

Lambda(1405) is mainly an antikaon-nucleon molecular state.

The model reproduces experimental pi Sigma spectra.

Provides constraints on subthreshold Kbar N interactions.

Abstract

The properties of the Lambda(1405) resonance are key ingredients for determining the antikaon-nucleon interaction in strangeness nuclear physics, and the novel internal structure of the Lambda(1405) is of great interest in hadron physics, as a prototype case of a baryon that does not fit into the simple three-quark picture. We show that a quantitative description of the antikaon-nucleon interaction with the Lambda(1405) is achieved in the framework of chiral SU(3) dynamics, with the help of recent experimental progress. Further constraints on the Kbar N subthreshold interaction are provided by analyzing pi Sigma spectra in various processes, such as the K-d -> pi Sigma n reaction and the Lambda_c -> pi pi Sigma decay. The structure of the Lambda(1405) is found to be dominated by an antikaon-nucleon molecular configuration, based on its wavefunction derived from a realistic Kbar N potential and the compositeness criteria from a model-independent weak-binding relation.