Speaker
Description
COMPASS experiment at CERN had a wide physics programme. One of its cornerstones were studies of hadron production in deep inelastic scattering (DIS), which can be interpreted in the transverse-momentum-dependent (TMD) factorisation framework, allowing to access the distributions of polarisation and transverse momentum of quarks within the nucleon in the language of TMD PDFs, and the hadronisation in terms of TMD fragmentation functions. In the 20 years of data taking from 2002 to 2022, unique data sets have been collected with high-energy muon beam and unpolarised and transversely polarised proton and deuteron targets, allowing for measurements that had a high impact on the knowledge of the transversity (transverse counterpart of the helicity PDF) and the other TMD parton distributions. The talk will focus on the unique data collected with a liquid hydrogen target in 2016 and with a transversely polarised deuteron target in 2022, which significantly improve the knowledge of the d-quark transversity and are yet to yield a number of interesting results on the other TMD distributions.