# Using a new analysis method to extract excited states in the scalar meson sector

## TL;DR

This paper introduces AMIAS, a novel statistical analysis method for extracting excited states in the scalar meson sector, especially effective with noisy data and multiple states, offering advantages over traditional GEVP techniques.

## Contribution

The paper presents the AMIAS method as an alternative to GEVP for analyzing correlators with multiple states and noisy data in meson spectroscopy.

## Key findings

- AMIAS effectively extracts excited states in scalar mesons.
- AMIAS performs well with noisy correlator data.
- Advantages over GEVP include better handling of multiple states and noise.

## Abstract

We explore a method to extract energy eigenstates, called Athens Model Independent Analysis Scheme (AMIAS), which is an alternative to solving standard Generalized Eigenvalue Problems (GEVP). The method is based on statistically sampling the space of fit parameters according to the $\chi^2$ value of the fit function. The method is particularly suited for correlators or correlation matrices with strong contributions from several energy eigenstates and for rather noisy data, e.g. for correlators with disconnected and partly disconnected diagrams. We apply the method to the analysis of the $J^P = 0^+$ channel in the context of our investigation of the $a_0(980)$ meson and point out advantages compared to the GEVP.