Track-based alignment of the CMS Muon System
The muon system of the CMS experiment provides fast muon trigger decisions, muon identifications, and muon trajectory measurements. The CMS muon system consists of drift tube chambers in central part and cathode strip chambers in forward parts complimented by trigger system consisting of resistive plate chambers distributed in both regions. The performance of the muon system depends on a precise knowledge of the positions and orientations of all its elements within the CMS detector. We present track-based alignment technique which uses muon tracks reconstructed in pp collision data at the LHC to align the muon system elements with respect to the inner silicon tracker. Iterative algorithm for the track-based alignment has been designed and implemented in the CMS software framework. We discuss details of the algorithm, results of the several years of CMS operation, methods utilized to evaluate the systematic uncertainties of the alignment parameters, achieved precision of the algorithm and improved muon momentum resolution. We also present plans for upgrade and future development.