SIR Physics Investigation Abstract
THE ALIGNMENT OF THE CENTRAL PRESHOWER DETECTOR
Presenter:
Steven Harris, Illinois Mathematics and Science Academy
Advisor:
Dr. Alan Magerkurth, Fermi National Accelerator Laboratory
Abstract:
The Central Preshower Detector (CPS) is a sub-detector of DØ, one of the two experiments using the Tevatron at Fermilab. The CPS may be misaligned relative to its nominal position, degrading the resolution of the CPS position measurements. We present the measurement of the CPS alignment and the derivation of corrections to the CPS cluster positions. Using a sample of electrons from Z decays, we compare CPS cluster positions with track extrapolations and calculate Delta Phi and Delta z. Using Delta Phi and Delta z, histograms were fit to search for possible misalignments. We find evidence for a shift in the x-y plane of 0.5 millimeters in the direction of -29° from the nominal position. We derive corrections to the CPS position measurement for this misalignment. Applying this correction improves the position resolution of the detector by approximately 5.4%. We continue to look for additional corrections to further improve the detector resolution.