Effizienzstudien des CMS Top-Taggers für stark geboostete Top-Quarks

Serge Rosen
Aug 2013

Thesis Type:

This bachelor thesis presents a study of the CMS Top-Tagger's efficiency for highly-boosted top quarks. These top quarks provide a probe for various models of new physics, as many theories predict new particles that decay into a pair of highly-boosted top quarks. The thesis uses the complete 2012 data sample recorded by the CMS detector at the LHC at a center-of-mass energy of 8 TeV. The data sample equals a total integrated luminosity of 19.6 fb$^{-1}$.
The efficiency's dependence on transverse momentum, pseudorapidity, hadronic activity, the number of primary vertices, and the number of jets is studied. Additionally, the top-tagged jets' ability to contain all three top quark decay products is examined.
The total measured efficiency is found to be $14.9\% \pm 1.2 \%$ with peak efficiencies of up to $40.6\% \pm 5.7 \%$. A dependency on the jet transverse momentum and pseudorapidity is observed with peaks around $p_{T} = 600$ GeV and $|\eta| = 0$ respectively.