Substructure of high-p_T Jets at the LHC

TL;DR

This paper investigates the substructure of high-p_T jets at the LHC, demonstrating how jet shape observables can distinguish between QCD jets and those from highly-boosted heavy particles, aiding background reduction.

Contribution

It introduces and analyzes jet shape observables like planar flow and angularities, showing their effectiveness in differentiating jet origins using perturbative and Monte Carlo methods.

Findings

Jet shape observables can distinguish QCD jets from heavy particle decays.

Perturbative analysis supports the use of these observables for massive jets.

Monte Carlo results confirm the discriminating power of the proposed shapes.

Abstract

We study high-pt jets from QCD and from highly-boosted massive particles such as tops, W, Z and Higgs, and argue that infrared-safe observables can help reduce QCD backgrounds. Jets from QCD are characterized by different patterns of energy flow compared to the products of highly-boosted heavy particle decays, and we employ a variety of jet shapes, observables restricted to energy flow within a jet, to explore this difference. Results from Monte Carlo generators and arguments based on perturbation theory support the discriminating power of the shapes we refer to as planar flow and angularities. We emphasize that for massive jets, these and other observables can be analyzed perturbatively.