CMS tracker alignment strategy and first results obtained from cosmic muon tracks

The all-silicon design of the CMS tracker poses new challenges in aligning the system with more than 15,000 independent modules. For optimal track-parameter resolution, the position and orientation of its modules need to be determined with a precision of better than few dozens of micrometres. Starting with the survey measurements and corrections provided by the hardware alignment system, the ultimate precision can be achieved with data from the silicon modules traversed in situ by charged particles. Several implementations of statistical algorithms allow to solve the optimization problem with the required accuracy in manageable time. Survey measurements and experience with the hardware alignment system are described as well as the selection of data samples used for track-based alignment and results from Monte Carlo studies. First CMS tracker alignment analysis results with cosmic track data are given.