Our group develops and performs the alignment of the CMS tracker with the Millepede algorithm, jointly with physicists from other CMS institutions. With almost 20,000 modules, the CMS tracker is the largest silicon tracking detector ever built. In order to achieve its optimal performance, the alignment of the individual detector modules must be known with an accuracy at the level of microns. This accuracy can only be achieved with many millions of tracks, which are used to extract of the order of 200,000 alignment parameters simultaneously.

The mathematical engine employed for solving this problem is the Millepede-II algorithm, which has been initially developed by V. Blobel in Hamburg and is now supported by members of the DESY CMS group in the framework of the analysis center of the Helmholtz Terascale alliance. Our group plays a leading role in the application of this algorithm at the CMS detector.