Track assisted techniques for jet substructure

The substructure of large-radius (large-$R$) jets provides an important handle to discriminate hadronic decays such as $W\to q{q}$, $H\to bb$, $H\to W(q{q})W^*(q{q})$, and $t\to W(q{q})b$ from QCD multijet backgrounds. Three algorithms that combine tracking and calorimeter information to calculate large-$R$ jet substructure observables are presented. The first algorithm makes use of both subjets and associated tracks to calculate new observables for standard large-$R$ jets. The other two newly developed algorithms use tracks and small-$R$ jets to construct new large-$R$ jets with observables that make use of information from both sets of inputs. These techniques are shown to improve the discrimination power of signal jets from background relative to the current ATLAS large-$R$ jet reconstruction techniques.