Dresden 2013 – wissenschaftliches Programm

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T: Fachverband Teilchenphysik

T 34: Top-Quarks 2

T 34.1: Gruppenbericht

Montag, 4. März 2013, 11:00–11:20, HSZ-04

B-tagging in CMS — Rebekka Höing, •Ivan Marchesini, and Alexander Schmidt — Institut für Experimentalphysik, Hamburg, Germany

The CMS experiment investigates high-energetic proton-proton collisions at the LHC, in order to broaden the knowledge of the Standard Model (SM) of particle physics and to discover possible new physics beyond the SM.

A large fraction of the CMS physics program relies on the identification 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 or the presence of soft leptons produced during their decay.

The CMS detector, with its excellent tracking system, robust lepton identification and finely segmented calorimeters, is well suited to the task of identification of b-jets (b-tagging). This talk gives an overview of the large variety of b-tagging algorithms and the measurement of their performance with data collected in 2011 and 2012. The algorithms described are based either on the identification of tracks displaced from the primary proton-proton collision, the reconstruction of secondary vertices or the presence of soft leptons inside jets. Some algorithms combine this information using multivariate techniques.

This talk discusses also the performance of b-tagging with upgraded CMS detector and high pile-up conditions, which will be faced during the high-energy collisions at 13 TeV planned to start in 2014.