Track and Vertex Reconstruction with the CMS Detector at LHC

Because of the high charged particle multiplicity expected in proton-proton collisions at the LHC experiment,track and vertex reconstructions are challenging tasks. Main track and vertex reconstruction techniques used in the CMS experiment are described in the following. Both the track and vertex reconstruction problems can be decomposed into a pattern recognition stage and an estimation of the track and vertex parameters. Main algorithms used in CMS are based on the least-squares methods, but depending on the specific application robustifications of the least-squares algorithms can be more suitable. Several robustification techniques will be described.