Longitudinal spin structure of the nucleon: COMPASS legacy

International audienceThe COMPASS collaboration has dedicated a large fraction of its already twenty year long existence to the study of the polarised structure of the nucleon. This presentation addresses two of the investigated aspects: inclusive measurements and direct measurements of the gluon polarised PDF, Δg. In the first case, a summary of what constitutes COMPASS legacy is presented. This covers the actual measurements of structure function g 1, at both high and low Q 2, and the information extracted from them in terms of polarised PDFs, axial charge and Bjorken sum rule. In particular, the quark spin contribution to the nucleon spin is determined to be 0.26 < Δ∑ < 0.36 and from COMPASS data alone the Bjorken sum rule is verified to 9% accuracy. In the second case, the latest developments in the analysis of our data on semi-inclusive single-hadron production at high-pT are reported