New measurements of transverse spin asymmetries at COMPASS

The recent developments in the description of the 3D structure of the nucleon have highlighted the relevance of SIDIS measurements with transversely polarized nucleons. The phenomenological analyses have also highlighted how the scarcity of SIDIS data collected with neutron or deuterium targets limits the knowledge of the parton distribution functions, in particular for the d quark. In the year 2022, the COMPASS experiment at CERN took data using a transversely polarised deuteron target and a 160 GeV muon beam at CERN, to balance the existing proton target data. Detailed studies had shown how those data would lead to significant progress in the knowledge of the transversity distributions. First preliminary results for the Collins and Sivers asymmetries from part of the 2022 data have already been produced, they are in line with expectations and are shown here for the first time.