Workshop for young scientists with research interests focused on physics at FAIR

The HADES (High Acceptance Di-Electron Spectrometer) at the GSI Helmholtzzentrum für Schwerionenforschung investigates dilepton and strangeness production in elementary and heavy-ion collisions. In April - May 2012 HADES recorded 7 billion Au+Au events at a beam energy of 1.23 GeV/u with the highest multiplicities measured so far. The track reconstruction and particle identification in the high track density environment are challenging. Most important detector component for lepton identification is a Ring Imaging Cherenkov detector. Its main purpose is the separation of electrons and positrons from large background of charged pions produced in heavy-ion collisions. In order to improve lepton identification a new backtracking algorithm was developed. In this contribution we will show the results of a new backtracking algorithm compared to the currently applied method for 𝑒−/+ identification. Efficiency and purity of a reconstructed 𝑒−/+ sample will be discussed as well. Supported by BMBF (05P12RFGHJ), Helmholtz Alliance EMMI, HIC for FAIR, HGS-HIRe and H-QM.