N Jettiness: An Inclusive Event Shape to Veto Jets
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Stewart-2010-N Jettiness_ An Incl.pdf
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Author(s)
Tackmann, Frank
Waalewijn, Wouter Jonathan
Stewart, Iain W
Date Issued
August 2010
Journal
Physical review letters
Publisher
American Physical Society
Citation
Stewart, Iain, Frank Tackmann, and Wouter Waalewijn. “N Jettiness: An Inclusive Event Shape to Veto Jets.” Physical Review Letters 105.9 (2010): n. pag. © 2010 The American Physical Society
Version
Final published version
Abstract
Jet vetoes are essential in many analyses at the LHC and Tevatron. Typical signals have a specific number of hard jets or leptons, while backgrounds have additional jets. Vetoing undesired jets efficiently discriminates signal and background. For a sample with ≥N jets, the veto to give N energetic jets defines an “exclusive” N-jet cross section. This strongly restricts the phase space and causes large double logarithms in perturbation theory that must be summed. Jet vetoes are typically implemented using jet algorithms, yielding complicated phase-space restrictions, and reliance on leading-log parton-shower Monte Carlo simulations. We introduce a global event shape “N jettiness” τN [tau subscript N], which is defined for events with N signal jets. Requiring τN [tau subscript N]≪1 constrains radiation between the signal jets and provides a theoretically well-controlled jet veto. N jettiness yields a factorization formula with inclusive jet and beam functions.
MIT Department
Massachusetts Institute of Technology. Center for Theoretical Physics
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Laboratory for Nuclear Science
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1103/PhysRevLett.105.092002
