Investigating top tagging with Ym-Splitter and N-subjettiness

We study top-tagging from an analytical QCD perspective focussing on the role of two key steps therein: a step to find three-pronged substructure and a step that places constraints on radiation. For the former we use a recently introduced modification of Y-Splitter, known as Ym-Splitter, and for the latter we use the well-known N-subjettiness variable. We derive resummed results for this combination of variables for both signal jets and background jets, also including pre-grooming of the jet. Our results give new insight into the performance of top tagging tools in particular with regard to the role of the distinct steps involved.