COMPASS results on weighted Sivers asymmetry in SIDIS

The transverse momentum weighted asymmetries have been proposed since a long time to access the transverse momentum dependent parton distributions. The COMPASS Collaboration has recently measured the weighted Sivers asymmetries in deep inelastic lepton scattering off transversly polarised protons. The results are in agreement with the expectations based on the previous measurements of the standard Sivers asymmetries. They are briefly described here, together with a new point-by-point extraction of the first moment of the Sivers function.