Background suppression strategies for lowmass dileptons T'Galatyuk GSI Darmstadt, Germany

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Background suppression strategies for low-mass
dileptonsT.Galatyuk - GSI Darmstadt, Germany
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• Simulation tools
• Parameters for analysis
• Reduction of combinatorial background
• Efficiency of cuts

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UrQMD PLUTO ?
? (background sources) (? meson decay) 10k
central AuAu collisions at 25 AGeV ?
GEANT3
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Parameters for analysis

• gold target thickness 50 ?m
• symmetric magnetic field 7.5 kG
• no particles identification (all positive
  tracks)
• 10-4 ?- misidentification
• 0.6 momentum resolution

Minv distribution of all ee- pairs
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• two tracks, identified as tracks from ?0 Dalitz
  decay or from ? decay, are not used in
  combinatorics
• combinations between tracks from two different
  ? (?0), didn't considered

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0.6 lt cos ?pair lt -0.6
pt lt 0.2 GeV/c
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Invariant mass spectra
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