B Jet Identification In Cms

A large fraction of the CMS physics program relies on the identification (tagging) of jets containing the decay of a B hadron (b jets). The b jets can be discriminated from jets produced by the hadronization of light quarks based on characteristic properties of B hadrons, such as the long lifetime. An overview of the large variety of b-tagging algorithms and the measurement of their performance with data collected in 2011 and 2012 are presented in this paper. A special focus lies on new methods of b-tagging in jet substructure. Searches for new physics often focus on boosted final states characterized by particles with large transverse momenta, resulting in decay products of heavy particles tending to be collimated and reconstructed as a single jet, known as fat jet. In this case, the reconstruction of the fat jet substructure is necessary to identify the particle initiating the fat jet. The substructure reconstruction can significantly be improved by the identification of b jets.