Non-perturbative effects and soft-gluon dynamics in low-$p_T$ Drell-Yan production

TL;DR

This paper investigates non-perturbative QCD effects in low-$p_T$ Drell-Yan production using the PDF2ISR framework, analyzing intrinsic parton momenta, soft-gluon radiation, and the strong coupling at low scales against experimental data.

Contribution

It introduces and applies the PDF2ISR approach to systematically study non-perturbative effects in low-$p_T$ Drell-Yan processes, including detailed analysis of simulation techniques and strong coupling models.

Findings

Assessment of the sensitivity of experimental data to low-scale $oldsymbol{_s}$ behavior.

Comparison of different low-scale strong coupling models with experimental results.

Insights into the interplay of intrinsic transverse momentum and soft-gluon radiation.

Abstract

The transverse-momentum spectrum of Drell-Yan lepton pairs at small $p_T$ probes non-perturbative QCD effects, including intrinsic partonic transverse momentum and initial-state soft-gluon radiation. The novel approach PDF2ISR is employed to study the transverse-momentum spectrum of Drell-Yan lepton pairs in the small-$p_T(\ell\ell)$ region. This framework is particularly well suited for such investigations, as it provides a systematic treatment of the dominant non-perturbative effects and their interplay. In order to extract robust physical conclusions, a detailed analysis of the technical aspects involved in the simulation of the intrinsic transverse momenta of partons inside the proton, as well as the remnant recoil schemes, was carried out. Furthermore, different approaches for the treatment of the strong coupling at low scales were investigated and confronted with available experimental data. This comparison enabled an assessment of the sensitivity of the experimental measurements to the chosen low-scale behaviour of $\alpha_s$.