Final COMPASS Results on the Transverse-Spin-Dependent Azimuthal Asymmetries in the Drell-Yan Process
G.D. Alexeev et al. (COMPASS Collaboration), Phys. Rev. Lett. 133, 071902 (2024)
A fundamental prediction based on Quantum Chromodynamics (QCD) is the sign change of Sivers functions between deep inelastic scattering and Drell-Yan processes. This milestone test has been first accomplished by the COMPASS collaboration in 2015 transversely-polarized Drell-Yan run. The observed sign of Sivers functions is found to be consistent with the prediction of QCD. This work provides the analysis of the data of 2015 and 2018 years by COMPASS. The final combined results support that measured Sivers TMD azimuthal asymmetries are consistent with the fundamental QCD prediction of a sign change of naive time-reversal-odd TMD PDFs when comparing the Drell-Yan process with deep inelastic scattering.
Journal Links: https://doi.org/10.1103/PhysRevLett.133.071902