Tracking the Identities of Boosted Particles

TL;DR

This paper demonstrates that using tracking information in collider detectors enhances the identification of boosted massive particles by combining radiation pattern variables with traditional mass-based variables, significantly improving tagging efficiency.

Contribution

It introduces a method to combine tracking-based radiation variables with jet mass for better boosted particle identification, showing improved statistical significance in W jet tagging.

Findings

Combining tracking variables with jet mass improves tagging significance by 1.6 times.

Adding N-subjettiness further increases significance to 1.8.

Tracking information provides complementary discrimination power.

Abstract

We show that the tracking system in a collider detector can be used to efficiently identify boosted massive particles from their QCD backgrounds. We examine variables defined with tracking information which are sensitive to jet radiation patterns, including charged particle multiplicity and N-subjettiness. These variables are barely correlated with variables sensitive to the hard splitting scale in the jet, such as the filtered jet mass. Therefore these two kinds of variables should be combined to optimize the discriminating power. We illustrate the method with $W$ jet tagging. It is shown that for jet PT=500 GeV, one can gain a factor of 1.6 in statistical significance by combining filtered jet mass and charged multiplicity, over filtered mass alone. Adding N-subjettiness increases the factor to 1.8.