Speaker
Description
Abstract: Studies of the transverse-spin dependent azimuthal asymmetries in the Drell-Yan process permit to access the spin-dependent structure of the nucleon and especially to test the limited universality of its transverse-momentum dependent parton distributions. In 2015 and 2018 the COMPASS Collaboration at CERN performed measurements of the $\pi^-$p $\rightarrow \mu^+\mu^-$X reaction at 190 GeV/$c$ pion beam and transversely polarised NH$_3$ target. This study covers the measurement of Transverse Spin Asymmetries in Drell-Yan processes, and in particular, introduces a novel approach, in contrast to the conventional one, where the asymmetries were weighted by powers of a transverse momentum of the dimuon system with respect to the beam. This method facilitates the extraction of the transverse-momentum dependent parton distribution functions and opens an easy access to their certain $k_{\rm T}^2$ moments. Results of these analyses together with a comparison with results obtained in the semi-inclusive muon production will be presented.
