Study of the Hadron Structure Using the Polarised Drell-Yan Process at COMPASS

The COMPASS experiment at CERN is one of the leading experiments studying the nucleon structure. The Parton Distribution Functions and the Transverse Momentum Dependent Parton Distribution Functions were extensively studied at COMPASS using Semi-Inclusive Deep Inelastic Scattering measurements until 2012. In 2015 the data taking was dedicated to the study of the polarised DrellYan process. COMPASS scattered a negative pion beam of 190 GeV/c off a transversely polarised proton target, with the goal of accessing the TMD PDFs of both hadrons (pions and protons). This can be achieved by measuring the target polarisation (in)dependent azimuthal asymmetries of produced oppositely charged muons. Since the DY data cover the same kinematic region as the SIDIS data collected with a transversely polarised target, COMPASS has the unique opportunity to test the sign change predicted by QCD of the Sivers TMD at the same hard scale in both processes. Preliminary distributions of collected DY data and estimation of projected asymmetry uncertainties are presented.