Jet Dipolarity: Top Tagging with Color Flow
  A new jet observable, dipolarity, is introduced that can distinguish whether a pair of subjets arises from a color singlet source. This observable is incorporated into the HEPTopTagger and is shown to improve discrimination between top jets and QCD jets for moderate to high pT. 
Anson Hook, Martin Jankowiak, Jay G. Wacker
hep-ph