Azimuthal angular correlation as a new boosted top jet substructure

TL;DR

This paper introduces a novel method to analyze the azimuthal angular correlation among decay products of highly boosted top quarks, enabling measurement of top quark polarization as a probe for new physics.

Contribution

It demonstrates that the azimuthal angular correlation can be measured in hadronic top decays and used to determine the top quark's longitudinal polarization.

Findings

Azimuthal correlation is measurable in hadronic boosted top decays.

Correlation magnitude relates to top quark polarization.

Potential to probe new physics through top polarization.

Abstract

When a top quark is highly boosted, the $W$ boson from its decay has a substantial linear polarization that results in a $\cos 2\phi$ azimuthal angular correlation among the top decay products. We show that this correlation can be measured for hadronically decayed boosted tops, and its magnitude provides a way to measure the longitudinal polarization of top quark, which is an important probe of new physics that couples to top sector.