Speaker
Nikola Lazar Whallon
(University of Washington (US))
Description
High $p_{T}$ (``boosted'') Higgs bosons decaying into a pair of $b$-quarks are an important signature for many physics searches in Run 2. The reconstruction and identification of such signatures relies mainly on the long-lived nature of the $b$-hadrons arising from the fragmentation of the $b$-quarks. Several advanced Higgs boson tagging techniques are presented here, including the reconstruction of the $b$-hadrons as subjets, the reconstruction of the vertices from the $b$-hadron decays, and the combination
of this information into a boosted decision tree (BDT). In addition, new subjet tagging techniques are investigated: the use of variable radius track jets and of exclusive $k_{T}$ calorimeter subjets, as well as a multiple secondary vertex (MSV) algorithm to reconstruct simultaneously the decay chain of both $b$-hadrons. The best performing Higgs boson tagger is found to be a BDT combination of the MSV algorithm and the subjet-based $b$-tagging algorithms.
Primary author
ATLAS Collaboration
(CERN)
