Four-dimensional formulation of the sector-improved residue subtraction scheme

TL;DR

This paper presents a comprehensive four-dimensional formulation of the STRIPPER subtraction scheme for NNLO QCD calculations, enabling the use of 't Hooft-Veltman regularization and broadening its applicability.

Contribution

It extends the STRIPPER scheme to arbitrary processes with multiple colored partons and incorporates 't Hooft-Veltman regularization, improving flexibility and computational efficiency.

Findings

Successfully applied to top-quark pair production in gluon fusion

Enables use of four-dimensional resolved states with HV regularization

Provides a complete formulation for processes with multiple partons

Abstract

Four years ago, one of us introduced a novel subtraction scheme for the evaluation of double-real radiation contributions to cross sections at next-to-next-to-leading order (NNLO) in QCD. This approach, named SecToR Improved Phase sPacE for Real radiation (STRIPPER), has already found several non-trivial applications. In particular, it has allowed for the determination of NNLO corrections to hadronic top-quark pair production, fully differential top-quark decays, inclusive semileptonic charmless b-quark decays, associated Higgs boson and jet production in gluon fusion, muon decay spin asymmetry, and t-channel single-top production. Common to these calculations was the use of conventional dimensional regularization (CDR). In this publication, we present a complete formulation of the subtraction scheme for arbitrary processes with any number of colored partons in the final state, and up to two partons in the initial state. Furthermore, we modify the integrated subtraction terms of the double-real radiation to enable the introduction of the 't Hooft-Veltman version of dimensional regularization (HV), in which resolved states are four-dimensional. We demonstrate the correctness of our approach on the example of top-quark pair production in the gluon fusion channel.