Speaker
Description
The exploration of the transverse spin structure of the nucleon by measuring the transverse-spin-dependent azimuthal asymmetries in Drell-Yan process is one of the main topics of the phase-II research programme of the COMPASS experiment (CERN, SPS-M2 beamline).
In 2015 and 2018 the experiment performed Drell-Yan measurements using a 190 GeV $\pi^-$ beam interacting with a transversely polarized $NH_3$ target and unpolarized tungsten material. The angular coefficients \lambda, \mu and \nu that describe the unpolarized part of the Drell-Yan cross section have been extracted from the data collected with tungsten target. Obtained results provide important information to study various perturbative and non-perturbative QCD effects. Performed polarized measurements of the Sivers and other transverse azimuthal asymmetries in Drell-Yan provide a unique possibility to test predicted in QCD (pseudo-)universal features of related transverse momentum dependent parton distribution functions.
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.
