Measurement of the Lambda(1405) in proton proton reactions with HADES

Abstract

We present an analysis of the Lambda(1405) resonance in p+p reactions at a kinetic beam energy of 3.5 GeV, measured by the High Acceptance Di-Electron Spectrometer (HADES). The resonance is reconstructed in the two charged decay channels Sigma^(+/-) pi^(-/+), with help of a kinematic refit, which improves the mass resolution. The high misidentification of pions and protons as kaons required the development of a sophisticated sideband analysis, which can describe the misidentification background quite well.