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T: Fachverband Teilchenphysik

T 75: Supersymmetrie 4

T 75.1: Group Report

Wednesday, March 26, 2014, 16:45–17:05, P4

Identification of b-quark jets in boosted topologies — Rebekka Höing, •Ivan Marchesini, Alexander Schmidt, and Emanuele Usai — Universität Hamburg

As the excluded mass regions for new physics beyond the Standard Model continue to increase, searches often focus on boosted final states characterized by particles with large transverse momenta. In the boosted regime the resulting decay products for hadronic decays of heavy particles tend to be collimated and can fall within a single jet, known as fat-jet. In this case, selections based on multiple jet searches cannot be applied and jet substructure is necessary to identify (tag) the particle initiating the jet. Substructure methods can be significantly improved by the identification of jets originating from bottom quarks (b-jets). This talk presents recent developments from the CMS Collaboration in commissioning b-tagging algorithms in boosted topologies, both on fat-jets and on their subjets. A particular challenge is the measurement of the b-tagging performance in these topologies. The standard efficiency measurements are performed on isolated jets in the resolved regime and are therefore not applicable. A dedicated validation of b-tagging algorithms in the boosted regime is presented, based on collider data recorded in proton-proton collisions at √s = 8 TeV with the CMS detector in the year 2012.