Angular distributions of Drell-Yan leptons in the TMD factorization approach

TL;DR

This paper investigates the angular distributions of Drell-Yan leptons using TMD factorization, incorporating kinematic power corrections to accurately describe angular coefficients and determine the Boer-Mulders function from experimental data.

Contribution

It provides a comprehensive TMD-based analysis of Drell-Yan angular distributions, including KPCs, at high perturbative order, and extracts the Boer-Mulders function from ATLAS data.

Findings

Good agreement with experimental data within TMD applicability

KPCs enable frame-independent description with leading-twist TMDs

Boer-Mulders function determined from ATLAS measurements

Abstract

We present a comprehensive study of the angular structure functions for Drell-Yan leptons in $Z/\gamma$-boson production within the framework of the transverse momentum dependent (TMD) factorization theorem, including kinematic power corrections (KPCs). We find good agreement with the data in the applicability region of the TMD factorization theorem. The inclusion of KPCs allows us to describe all angular coefficients in a frame-independent manner using only the leading-twist TMD distributions: the unpolarized and the Boer-Mulders functions. The value of the Boer-Mulders function is determined using the ATLAS measurement of the $A_2$ angular coefficient. The analysis is performed at N$^4$LL perturbative order. Additionally, we discuss the technical implementation and impact of KPCs on the phenomenology of TMD distributions.