Resurrecting the Dead Cone

TL;DR

This paper proposes using jet substructure techniques at the LHC to directly observe the dead cone effect in radiation patterns around boosted top quarks, enabling experimental validation of a fundamental gauge theory phenomenon.

Contribution

It introduces a novel method to detect the dead cone effect in collider experiments using jet substructure analysis.

Findings

Potential to observe the dead cone effect with 300/fb data at the LHC.

First direct experimental evidence of the dead cone effect.

Validation of the universality of radiation suppression in gauge theories.

Abstract

The dead cone is a well-known effect in gauge theories, where radiation from a charged particle of mass m and energy E is suppressed within an angular size of m/E. This effect is universal as it does not depend on the spin of the particle nor on the nature of the gauge interaction. It is challenging to directly measure the dead cone at colliders, however, since the region of suppressed radiation either is too small to be resolved or is filled by the decay products of the massive particle. In this paper, we propose to use jet substructure techniques to expose the dead cone effect in the strong-force radiation pattern around boosted top quarks at the Large Hadron Collider. Our study shows that with 300/fb of 13-14 TeV collision data, ATLAS and CMS could obtain the first direct evidence of the dead cone effect and test its basic features.