Searching for the dead cone effects with iterative declustering of heavy-flavor jets

Abstract

We present a new method to expose the dead cone effect at colliders using iterative declustering techniques. Iterative declustering allows to unwind the jet clustering and to access the subjets or branches at different depths of the jet tree. Our method consists on declustering the heavy flavour-tagged jet using Cambridge-Achen algorithm following the branch containing the heavy flavour at each step and registering the kinematics of the complementary untagged prong. The kinematics of the complementary untagged prong fill a Lund map representing the gluon radiation off the heavy flavour quark at each step of the vacuum shower. Using Pythia8 MC, we show that a simple cut on the Lund plane introduced by log($k_{T}$) $> 0$, suppresses hadronisation effects and the angular separation between the jet prongs becomes very sensitive to flavour effects. A clear suppression for heavy flavour jets relative to inclusive jets in the region of splitting angles delimited by the relation $\theta < m_{Q}/E$ is observed, where $m_{Q}$ is the mass of the heavy quark and $E$ is the energy of the radiator or splitting prong.