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T: Fachverband Teilchenphysik
T 67: Detektorsysteme III
T 67.9: Talk
Wednesday, March 27, 2019, 18:00–18:15, S03
Systematic studies of track-based alignment of the CMS tracker — •Josry Metwally — DESY, Hamburg, Germany
The CMS (Compact Muon Solenoid) tracker is the largest silicon tracker in the world, consisting of a large number of pixel (1856) and strip (15148) modules to ensure a precise reconstruction of tracks and vertices. In order to fully exploit the precision of the local reconstruction of the silicon modules, we use a track-based approach to align the modules. The number of alignment parameters is of the order of 100k and its determination is achieved by the means of the linear least-squares method (χ2), while residuals between the hits and the reconstructed track are minimised. Continuous transformations called weak modes corresponding to transformations to which the χ2 fit is not very sensitive are one of the major challenges of track-based alignment. In this talk, systematic studies to control weak modes are presented.