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 experiments, track and vertex reconstructions are challenging tasks. The main track and vertex reconstruction techniques used in the CMS experiment are described in the following. Both the track and vertex reconstruction algorithms can be decomposed into a pattern recognition step followed by the estimate of the track and vertex parameters. The main algorithms used in CMS are based on the least-squares methods, but depending on the specific application improvements of the simple least-squares algorithms are found useful to enhance the performance.