Sivers Asymmetry with QCD Evolution

TL;DR

This paper investigates the Sivers asymmetry in various high-energy processes, incorporating QCD evolution and a universal Sudakov factor, and makes predictions for future experiments to test the Sivers function's sign change.

Contribution

It introduces a universal non-perturbative Sudakov factor for describing Sivers asymmetry data across multiple processes and performs a global fit to predict asymmetries in unmeasured reactions.

Findings

Successfully describes SIDIS, DY, and W/Z production data

Provides predictions for future Drell-Yan and W asymmetries

Supports the sign change hypothesis of the Sivers function

Abstract

We analyze the Sivers asymmetry in both Drell-Yan (DY) production and semi-inclusive deep inelastic scattering (SIDIS), while considering properly defined transverse momentum dependent parton distribution and fragmentation functions and their QCD evolution. After finding a universal non-perturbative spin-independent Sudakov factor that can describe reasonably well the world's data of SIDIS, DY lepton pair and $W/Z$ production in unpolarized scatterings, we perform a global fitting of all the experimental data on the Sivers asymmetry in SIDIS from HERMES, COMPASS and Jefferson Lab. Then we make predictions for the asymmetry in DY lepton pair and $W$ boson production, which could be compared to the future experimental data in order to test the sign change of the Sivers function.