Identifying boosted objects with N-subjettiness and linear k-means clustering
Name
746925556-MIT.pdf
Description
Full printable version
Size
4.2 MB
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Checksum (MD5)
070885a479c9642f069b07eb5e8ba051
Author(s)
Van Tilburg, Ken
Advisor(s)
Jesse Thaler.
Date Issued
2011
Publisher
Massachusetts Institute of Technology
Abstract
In this thesis, I explore aspects of a new jet shape - N-subjettiness - designed to identify boosted hadronically-decaying objects (with a particular focus on tagging top quarks) at particle accelerators such as the Large Hadron Collider. Combined with an invariant mass cut on jets, N-subjettiness is a powerful discriminating variable for tagging boosted objects such as top quarks and rejecting the fake background of QCD jets with large invariant mass. In a crossover analysis, the N-subjettiness method is found to outperform the common top tagging methods of the BOOST2010 conference, with top tagging efficiencies of 50% and 20% against mistag rates of 4.0% and 0.19%, respectively. The N-subjettiness values are calculated using a new infrared- and collinear-safe minimization procedure which I call the linear k-means clustering algorithm. As a true jet shape with highly effective tagging performances, N-subjettiness has many advantages on the experimental as well as on the theoretical side.
Description
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics; and, (S.B.)--Massachusetts Institute of Technology, Dept. of Mathematics, 2011.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 57-59).
Subjects
Physics.
Mathematics.
MIT Department
Massachusetts Institute of Technology. Department of Mathematics
Massachusetts Institute of Technology. Department of Physics
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