Transverse-Spin Asymmetries in COMPASS Drell-Yan Data

Studies of the transverse-spin dependent azimuthal asymmetries in the Drell-Yan process provide insight into the spin-dependent structure of the nucleon and test the limited universality of its transverse momentum dependent parton distributions, which are also studied in deep inelastic scattering. In 2015 and 2018, the COMPASS Collaboration at CERN conducted measurements of the $\pi^{-} \text{p}$ $\rightarrow \mu^{+}\mu^{-}\text{X}$ reaction using a 190 GeV/$c$ pion beam and a transversely polarized NH$_{3}$ target. The results of this analysis were presented, including findings obtained with a novel approach that weights the asymmetries by powers of the transverse momentum of the dimuon system relative to the beam. This method overcomes the convolution over the intrinsic transverse momentum and provides straightforward access to certain $k_{\text{T}}^{2}$ moments of the transverse momentum dependent parton distribution functions.