Lambda(1405) and kaonic few-body states in chiral dynamics

TL;DR

This paper reviews the structure of Lambda(1405) within chiral dynamics, extending the hadronic molecular concept to kaonic few-body states, predicting quasibound states involving kaons near break-up thresholds.

Contribution

It demonstrates that Lambda(1405) and similar states can be understood as hadronic quasibound states, extending the molecular picture to kaonic few-body systems.

Findings

Lambda(1405) described as a KbarN quasibound state

Prediction of kaonic few-body quasibound states like KbarNN, KbarKN, KbarKK

Identification of f_0(980) and a_0(980) as KbarK states

Abstract

The present status of the Lambda(1405) structure study in chiral dynamics is briefly reviewed. It turns out that the Lambda(1405) resonance can be described by hadronic dynamics. The idea of the hadronic molecular state is extended to kaonic few-body states. It is concluded that, due to the fact that K and N have similar coupling nature in s-wave Kbar couplings, there are few-body quasibound states with kaons systematically just below the break-up thresholds, like KbarNN, KbarKN and KbarKK, as well as Lambda(1405) as a KbarN quasibound state and f_0(980) and a_0(980) as KbarK.