# Diagrammatic resummation of leading-logarithmic threshold effects at next-to-leading power

## TL;DR

This paper demonstrates a diagrammatic method to resum next-to-leading power threshold logarithms at leading-logarithmic accuracy in QCD processes with color-singlet final states, extending traditional resummation techniques.

## Contribution

It introduces a novel diagrammatic approach to resum NLP threshold logarithms at LL accuracy in QCD, generalizing existing methods beyond leading power.

## Key findings

- NLP threshold logarithms can be resummed at LL accuracy.
- The method applies to any QCD process with a color-singlet final state.
- Comparison with other approaches highlights its effectiveness.

## Abstract

Perturbative cross-sections in QCD are beset by logarithms of kinematic invariants, whose arguments vanish when heavy particles are produced near threshold. Contributions of this type often need to be summed to all orders in the coupling, in order to improve the behaviour of the perturbative expansion, and it has long been known how to do this at leading power in the threshold variable, using a variety of approaches. Recently, the problem of extending this resummation to logarithms suppressed by a single power of the threshold variable has received considerable attention. In this paper, we show that such next-to-leading power (NLP) contributions can indeed be resummed, to leading logarithmic (LL) accuracy, for any QCD process with a colour-singlet final state, using a direct generalisation of the diagrammatic methods available at leading power. We compare our results with other approaches, and comment on the implications for further generalisations beyond leading-logarithmic accuracy.