Alignment of the CMS tracker and track reconstruction with collision data in CMS

The CMS all-silicon tracker was aligned using more than three million cosmic rays particles. The positions of the modules were determined with respect to cosmic ray trajectories to a precision of 3 − 4 μm in the barrel and 3 − 14 μm in the endcap in the most sensitive coordinate. The trajectories of charged particles produced in the LHC collisions were reconstructed and their momenta were measured in the 3.8 T solenoidal magnetic field. Reconstructed tracks are used to determine the position of the primary interaction vertex in the event and to monitor the position of the colliding beams. The tracks have been used further to reconstruct the hadronic decays of several mesons, including K S , D∗, Λ, and φ. The performance of track reconstruction has been measured in the data and is compared to the expectation from simulation.