Electron Identification Using Bremsstrahlung Radiation Daniel Kapec Main
Electron Identification Using Bremsstrahlung Radiation Daniel Kapec Main Supervisor: Anthony Morley Secondary Supervisor: Dr. Alan Poppleton
The Big Picture • ATLAS Experiment • Electron identification – Plays a role in several important discovery channels
Detector Material Effects • Electrons – Low mass, energy loss dominated by bremsstrahlung radiation at high energies • Pions – Bremsstrahlung events suppressed by large mass – Scattering dominates track variations • Reconstruction must account for material effects – Run the Gaussian Sum Filter (GSF) on electron candidates
Track Reconstruction and Particle Identification • Track Reconstruction – Track seeds, Global Chi-Square Fitter • Electron Identification – Electromagnetic Calorimeter – TRT threshold measurement
Separation Using the TRT
CDF’s and Separation
Understanding the Separation
Radius of Largest Bremsstrahlung Event
Refining the Comparison
Refining the Comparison
Maintained Separation • Frequency of electrons with all TRT hits flagged as outliers dwarfs frequency for pions Electrons Pions
What’s Next • Use method on actual LHC data – Using Z->ee, create invariant mass distribution – Redo, using the Bremsstrahlung Energy Loss discrimination – Hopefully see significant background reduction
Trip to Rome
Special Thanks to… • Dr. Neal, Dr. Krisch, Dr. Goldfarb and Dr. Zhu • Anthony Morley • Dr. Poppleton
Questions
- Slides: 15