Physics Analysis in the ATLAS Muon Spectrometer Victoria A Moeller U of M CERN NSF REU Summer 2006
ATLAS Computing System Commissioning (CSC) Test – Beginning in Fall 2006, Testing: • • Tier-0 Scaling Distributed Data Management & Processing Analysis Tools & Distributed Analysis Full Software Chain Streaming Test Calibration & Alignment Trigger Chain
Preparing for the CSC Test • Developing Analysis Procedures – Testing, Updating, Validating • Performing Preliminary Comparison of Perfect and Mis-Aligned Geometries – Using Data Simulated with Perfect Geometry and Reconstructed with Realistic Geometry
Analysis Procedures – Obtaining and Installing a Grid Certificate – Registering with the ATLAS Virtual Organization – Locating Simulated Data Sets on castor and on the Grid, using DQ 2 – Transferring Data Sets between the Grid, castor, and lxplus – Installing and Running Athena for Reconstruction and Analysis – Running Jobs interactively, in batch, and on the Grid – Analyzing Athena-Aware n-tuples • Reconstructing with Mis-Aligned Geometry
Calibration & Alignment Test and the Muon Spectrometer Dx = -1. 75 mm Dy = 5. 25 mm • Perfect Geometry replaced with ‘Realistic’ Detector Conditions Dq. BOL~ 1 mrad Dq. BML~ 1. 3 mrad Dq. BIL~ 1. 8 mrad Dx = 3. 5 mm Dy = 3. 5 mm Dq = 0. – Real Muon Spectrometer Eventually Aligned to a Precision of 50 microns over 25 meters – Alignment Will Not be Perfectly Understood for Initial Data Dx = -3. 5 mm Dy = 3. 5 mm Dq = 0. Dx = 0. Dy = 0. y z Dx = 0. mm Dy = 7. mm Dq = 0. x
Z’ in ATLAS • pp Z’ + – Predicted by Grand Unified Theories – Possible Light Higgs Channel • Can be detected with statistical significance in LHC up to 2 Te. V Z’ mass • Z + - – Well Known Mass – Low Background – Used for Calibration • Z’/Z cross section ratio will distinguish between theoretical models
Preliminary Effect of Mis-Aligned Geometry on Z’ Measurement • Starting with 376 Reconstructed Events with Two Muons • Selected Events with – Opposite Charge – Fit Quality – Minimum Transverse Energy • For Perfect Geometry 328 Events • For Mis-Aligned Geometry 31 Events • Initial Analysis – Substantial Loss in Efficiency with Small Random Displacements • Lots of Investigation Still To Be Done!
Continuing Z and Z’ Analysis • Investigate Efficiency Loss • Obtain Data from the Grid • Run Jobs on the Grid • Test Efficiency in Z • ATLAS CSC Test – Reverse the Analysis • Simulate with Mis-Aligned Geometry and Reconstructing with Perfect Geometry
Acknowledgements Dr. Steven Goldfarb CERN National Science Foundation Ford University of Michigan
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