Investigation of the Lambda(1405) line shape observed in pp collisions

TL;DR

This paper investigates the complex line shape of the Lambda(1405) resonance observed in proton-proton collisions, analyzing interference effects and using data to constrain the resonance poles' positions.

Contribution

It introduces a phenomenological method to determine the relative contributions of the two Lambda(1405) poles from experimental data.

Findings

Interference effects significantly influence the observed line shape.

Data can constrain the positions of the two poles in the complex energy plane.

The study provides insights into the resonance's underlying structure.

Abstract

In this work we investigate different possible explanations for the observed low mass {\Lambda}(1405) signal associated to the production of the {\Lambda}(1405) in p+p reactions at 3.5 GeV beam kinetic energy measured by the HADES collaboration. We study the influence of interference effects between the {\Lambda}(1405) resonance and the non-resonant background. Furthermore, we present a phenomenological method to use the HADES data for determining the relative contribution of the two {\Lambda}(1405) poles and discuss to which extent the data can constrain the position of these poles in the complex energy plane.