Dynamical Threshold Enhancement and Resummation in Drell-Yan Production

TL;DR

This paper investigates how threshold effects and soft gluon emissions influence Drell-Yan production cross sections, using effective field theory to derive compact resummed formulas that improve accuracy in high-energy hadronic collisions.

Contribution

It introduces a new effective field theory approach to threshold resummation, providing compact, Landau-pole free expressions for Drell-Yan processes directly in momentum space.

Findings

Resummed cross sections evaluated at NNNLL order show improved precision.

Dynamical enhancement of threshold effects due to parton density fall-off at high x.

Analytical formulas match fixed-order calculations seamlessly.

Abstract

Partonic cross sections for the production of massive objects in hadronic collisions receive large corrections when the invariant mass of the initial-state partons is just above the production threshold. Since typically the center-of-mass energy of the hadronic collision is much higher than the mass of the heavy objects, it is not obvious that these contributions translate into large corrections to the hadronic cross section. Using a recent approach to threshold resummation based on effective field theory, we quantify to which extent the fall-off of the parton densities at high x leads to a dynamical enhancement of the partonic threshold region. With the example of Drell-Yan production, we study the emergence of an effective physical scale characterizing the soft emissions in the process. We derive compact analytical expressions for the resummed Drell-Yan cross section and rapidity distribution directly in momentum space. They are free of Landau-pole singularities and are trivially matched onto fixed-order perturbative calculations. Evaluating the resummed cross sections at NNNLL order and matching onto NNLO fixed-order calculations, we perform a detailed numerical analysis of the cross section and rapidity distribution in proton-proton collisions.