Next-to-leading power threshold corrections for finite order and resummed colour-singlet cross sections

TL;DR

This paper investigates next-to-leading-power threshold corrections in colour-singlet processes like Drell-Yan and Higgs production, demonstrating their numerical significance and comparing resummation formalisms.

Contribution

It provides the first detailed numerical assessment of NLP threshold corrections and compares soft-collinear effective theory with direct QCD approaches.

Findings

NLP logarithms are more impactful than higher-order LP resummation.

Excellent agreement between SCET and QCD when NLP LL terms are included.

NLP corrections are phenomenologically significant.

Abstract

We study next-to-leading-power (NLP) threshold corrections in colour-singlet production processes, with particular emphasis on Drell-Yan (DY) and single-Higgs production. We assess the quality of the partonic and hadronic threshold expansions for each process up to NNLO. We determine numerically the NLP leading-logarithmic (LL) resummed contribution in addition to the leading-power next-to-next-to-leading logarithmic (LP NNLL) resummed DY and Higgs cross sections, matched to NNLO. We find that the inclusion of NLP logarithms is numerically more relevant than increasing the precision to N$^3$LL at LP for these processes. We also perform an analytical and numerical comparison of LP NNLL + NLP LL resummation in soft-collinear effective theory and direct QCD, where we achieve excellent analytical and numerical agreement once the NLP LL terms are included in both formalisms. Our results underline the phenomenological importance of understanding the NLP structure of QCD cross sections.