Summing threshold logs in a parton shower

TL;DR

This paper presents a method to sum threshold logarithmic effects in parton shower Monte Carlo simulations, improving the accuracy of predictions for high-momentum fraction processes.

Contribution

It introduces a leading approximation technique to incorporate threshold logarithm summation into parton shower algorithms.

Findings

Enhanced accuracy in simulating high-momentum parton interactions

Effective summation of threshold effects at each order in _s

Improved predictions for steeply falling parton distributions

Abstract

When parton distributions are falling steeply as the momentum fractions of the partons increases, there are effects that occur at each order in $\alpha_s$ that combine to affect hard scattering cross sections and need to be summed. We show how to accomplish this in a leading approximation in the context of a parton shower Monte Carlo event generator.