New insights into antikaon-nucleon scattering and the structure of the Lambda(1405)

TL;DR

This paper presents a detailed analysis of antikaon-nucleon interactions using a coupled-channel Bethe-Salpeter approach, providing precise scattering parameters and insights into the Lambda(1405) resonance structure.

Contribution

It introduces a next-to-leading order chiral effective potential analysis of antikaon-nucleon scattering, accurately extracting scattering lengths and elucidating the Lambda(1405) two-pole structure.

Findings

Precise antikaon-proton scattering amplitudes

Accurate scattering lengths a0 and a1

Discussion of the two-pole structure of Lambda(1405)

Abstract

We perform a combined analysis of antikaon-nucleon scattering cross sections and the recent SIDDHARTA kaonic hydrogen data in the framework of a coupled-channel Bethe-Salpeter approach at next-to-leading order in the chiral expansion of the effective potential. We find a precise description of the antikaon-proton scattering amplitudes and are able to extract accurate values of the scattering lengths, a0=-1.81^+0.30_-0.28 + i 0.92^+0.29_-0.23 fm, a1=+0.48^+0.12_-0.11 + i 0.87^+0.26_-0.20 fm. We also discuss the two-pole structure of the Lambda(1405).