On the non-cancellation of infrared singularities in collisions of massive quarks

TL;DR

This paper investigates the infrared singularities in processes involving massive quarks, revealing their origin and how they violate the Bloch-Nordsieck theorem at higher orders in perturbative QCD.

Contribution

It provides a simple physical argument that clarifies the origin of uncanceled infrared singularities in heavy-quark initiated processes at NNLO.

Findings

Identifies the breakdown of the Bloch-Nordsieck theorem in massive quark processes.

Provides a simplified derivation of infrared singularities in heavy-quark collisions.

Clarifies the physical origin of infrared singularities at NNLO.

Abstract

We discuss the infrared structure of processes with massive quarks in the initial state. It is well known that, starting from next-to-next-to-leading order in perturbative QCD, such processes exhibit a violation of the Bloch-Nordsieck theorem, in that the sum of real and virtual contributions to partonic cross sections contains uncanceled infrared singularities. The main purpose of this paper is to present a simple physical argument that elucidates the origin of these singularities and simplifies the derivation of infrared-singular contributions to heavy-quark initiated cross sections.