# Structure, formation and decay of $\bar{K}NN$ system by Faddeev-AGS calculations

## TL;DR

This paper uses Faddeev-AGS calculations to analyze the $ar{K}NN$ system, demonstrating the potential to observe the $K^{-}pp$ quasi-bound state and branch points in $ar{K}N- ext{pi}\Sigma$ interactions through mass spectra.

## Contribution

It introduces a detailed Faddeev-AGS approach with various potentials to identify signatures of the $K^{-}pp$ state and branch points in experimental observables.

## Key findings

- Signature of $K^{-}pp$ quasi-bound state can be observed in mass spectra.
- Trace of branch points can be detected in the observables.
- Different interaction models consistently show these features.

## Abstract

The Faddeev AGS equations are solved for coupled-channels $\bar{K}NN-\pi\Sigma{N}$ system with quantum numbers $I=1/2$ and $S=0$. Using separable potentials for $\bar{K}N-\pi\Sigma$ interaction, we have calculated the transition probability for the $(Y_{K})_{I=0}+N\rightarrow\pi\Sigma{N}$ reaction. The possibility to observe the trace of $K^{-}pp$ quasi-bound state in the $\pi\Sigma{N}$ mass spectra was studied. Various types of chiral based and phenomenological potentials are used to describe the $\bar{K}N-\pi\Sigma$ interaction. It was shown that not only we can see the signature of the $K^{-}pp$ quasi-bound state in the mass spectra, but also, one can see the trace of branch points in the observables.