First Alignment of the Complete CMS Silicon Tracker

We present the first results of the full CMS Silicon Tracker alignment based on several millions reconstructed tracks from the cosmic data taken during the commisioning runs with the detector in its final position. The all-silicon design of the CMS Tracker poses new challenges in aligning a complex system with 15148 silicon strip and 1440 silicon pixel modules. For optimal track-parameter resolution, the position and orientation of its modules need to be determined with a precision of several micrometers. For those modules well illuminated by cosmic ray particles, the ultimate precision has been achieved with data from the silicon modules traversed in-situ by charged muons used in combination with survey measurements. The achieved resolution in all five track parameters is controlled with data-driven validation of the track parameter measurements near the interaction region, and tested against prediction with detailed detector simulation.