Speaker
Description
COMPASS is a fixed-target high energy physics experiment located at the M2 beamline of the Super Proton Synchrotron at CERN. The study of the spin structure of the nucleon by measuring nucleon spin (in)dependent azimuthal asymmetries in Drell-Yan process is one of the main topics of the phase-II research programme of the experiment.
In 2015 and 2018 COMPASS performed Drell-Yan measurements using a 190 GeV $\pi^-$ beam interacting with a transversely polarized NH$_{3}$ and unpolarized nuclear targets. The angular coefficients that describe the unpolarized part of the Drell-Yan cross section have been extracted from the data collected with tungsten target. The results obtained provide important information to study various perturbative and non-perturbative QCD effects. Performed polarized measurements of the Sivers and other transverse spin azimuthal asymmetries in Drell-Yan provide a unique possibility to test the (pseudo-)universality of the transverse momentum dependent parton distribution functions.
Measuring the same set of asymmetries in $J/\psi$ production may give an alternative access to parton distribution functions and serve as input for the study of $J/\psi$ production mechanisms.
In this talk recent preliminary results from the COMPASS Drell-Yan programme will be presented together with related measurements from other experiments and available model predictions.
