Chiral SU(3) theory of antikaon-nucleon interactions with improved threshold constraints

TL;DR

This paper employs chiral SU(3) theory to analyze antikaon-nucleon interactions, utilizing recent experimental data to refine coupled-channels models and predict properties of related resonances and interactions.

Contribution

It introduces an improved coupled-channels framework constrained by recent kaonic hydrogen data, enhancing predictions for antikaon-nucleon interactions and the $ar{K}$-nuclear spectrum.

Findings

Accurate constraints on meson-baryon amplitudes from kaonic hydrogen data

Predictions for $K^-$-neutron interactions and $ar{K}$-nuclear states

Discussion of uncertainties in subthreshold amplitude extrapolations

Abstract

$\bar{K}$-nucleon interactions are investigated in the framework of coupled-channels dynamics based on the next-to-leading order chiral SU(3) meson-baryon effective Lagrangian. A recent determination of the 1s shift and width of kaonic hydrogen enables us to set accurate constraints on the coupled-channels meson-baryon amplitudes in the strangeness $S=-1$ sector. Theoretical uncertainties in the subthreshold extrapolation of the coupled-channels amplitudes are discussed. Using this framework, we give predictions for $K^-$-neutron interactions and for the spectrum of the $\Lambda(1405)$ resonance. A simplified, effective three-channel model using leading order chiral SU(3) meson-baryon interactions is also constructed for convenient application in $\bar{K}$-nuclear few-body calculations.