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A Luminosity Detector for the F uture L inear C ollider. Ronen Ingbir. Prague Workshop. A Luminosity Detector for the F uture L inear C ollider. HEP Tel Aviv University. A. Analyses of detector + background MC B. Cross checks in Geant 4 C. Energy and Angular
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A LuminosityDetector for the Future Linear Collider Ronen Ingbir Prague Workshop A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
A. Analyses of detector + background MC B. Cross checks in Geant 4 C. Energy and Angular resolution improvement. Next Steps….. Tel Aviv University High Energy Physics Experimental Group R&D progress report Approach : Going back to ‘pure electron’ simulation Bhabha Beamstrahlung Beam spread A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Cell Size 1.3cm*2cm> 1.3cm*6cm< ~1 Radiation length ~1 Radius Moliere Detector Design 15 cylinders * 24 sectors * 30 rings = 10800 cells 8 cm 0.31 cm Silicon 28 cm 0.34 cm Tungsten R L 6.10 m A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Log. weight. E weight. Reconstruction Algorithm We explored two reconstruction algorithms: Events Num. The log. weight fun. was designed to reduce steps in a granulated detector : 1. Selection of significant cells. 2. Log. smoothing. A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Logarithmic Constant 400 GeV After selecting: We explored a more systematic approach. The first step is finding the best constant to use under two criteria: 1. Best resolution. 2. Minimum bias. Constant value Constant value A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Energy dependent constant The goal is to find a global weight function. Is the the log. weight constant really a constant ? Constant value A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Shower size Log. Weight selection Shower reconstruction What happens when we select the best log. weight constant ? Num. of Cells Num. of Sectors Energy portion (%) Num. of Cylinders Most of the information is in the selected cells. En>90% A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
24 sectors 48 sectors 0.63 0.46 0.00013 0.00013 Detector optimization Comparing new results : Improvement without changing the detectors granularity. Num. rings A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Detector optimization A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Angular resolution Results using ‘pure electron’ simulation Can we maintain same detector properties using a more ‘real’ MC ? Beam Energy (GeV) A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Azimuthal resolution Events Num. E weight. Log. weight. A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Log. constant 400 GeV Best constant value for is bigger then the one. Meaning: in this case best results are obtained by using ‘all the detector information’. Fixed non zero bias under investigation. Constant value Constant value A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
E weight. Fixed constant dependent const 100% 33% Log. weight Const function Different cell size requires different weight function. Low angle small cell size smaller constant value (like in rec) A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Shower size Log. Weight selection Shower reconstruction What happens when we select the best log. weight constant ? Num. of Cells Num. of Sectors Cell size determines selection mechanism Num. of Cylinders Energy portion (%) En>98% A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Azimuthal resolution Results using ‘pure electron’ simulation Beam Energy (GeV) A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Energy resolution Results using ‘pure electron’ simulation Acceptance cut Energy Resolution Beam Energy (GeV) A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Pure electrons Bhabha Bhabha Pure electrons Bhabha scattering BHWIDE MC Simulation Barbie -Geant 3.21 which includes detector description for Tesla detector The MC of physical process is the output of bhabha scattering The Barbie program was given to us by Leszek Suszycki Electron energy (GeV) A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Acceptance cut was based on the leakage 250GeV 26 mrad Events selection - old approach Gaussian fit and energy calibration based tail cut Detector signal A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
33 mrad New Acceptance Energy Resolution More systematic analyses results with new acceptance cut and improved resolution. A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Simulation distribution Distribution after acceptance and energy balance event selection R L Energy balance New approach in this study : Selecting events using information from both sides of the detector. Right signal - Left signal Left side detector signal Right side detector signal A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Angular-azimuthal symmetry 2 New approach : Selecting events which are back to back. The band cut must be wider than the relevant resolution. 1 A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Events selection Detector signal Detector signal Acceptance cut Energy balance cut Detector signal A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Energy resolution - Bhabha A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Angular resolution - Bhabha A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Background studies we included in the BHWIDE a background simulation routine called CIRCE. This was suggested to us byK. Moenig Beamspread Boogert & Miller note (0.05%) (hep-ex/0211021) Moenig talk in Zeuthen (0.1%) Barbie Detector simulation A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Background studies A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Cut Value Resolution Relative to Resolution Acceptance Energy balance ~85% Angular symmetry ~14% Azimuthal symmetry <20% Selecting events in background MC A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Ntuple Nocuts Withcuts Pure electrons 31% 29% Bhabha 42% 24% Bhabha + Beamstrahlung 45% 24% Bhabha + Beamstrahlung + Beam spread (0.05%) 46% 25% Bhabha + Beamstrahlung + Beam spread (0.5%) 49% 29% Energy resolution A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Angular resolution A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Event rate: Luminosity: Future linear collider precision goal: Luminosity Measurement approach : taking a known process – Bhabha scattering. R&D approach: R&Dstatus : A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Conceptual experiment & real life algorithm In real life we have a MC to help us understand our measurements. We want to improve by a factor of 10, but maybe a 10% disagreement between data and MC is exactly the 10th factor we need. The question is how well does our MC will describe the future data ? Working with both sides of the detector and looking at the difference between the reconstructed properties: (In real life we don’t have generated properties) A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
How far are we ? How well will our MC describe the future DATA ? 35% 11% 1.’DATA’ = Reality MC 2. Real life algorithm A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
Summary and future goals Using a more systematic approach results with improved reconstruction algorithms and improved resolutions. Our next step will be to explore further the ‘real life’ approach. Final detector design recommendation. A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University
The End A Luminosity Detector for the Future Linear Collider HEP Tel Aviv University