Understanding the internal structure of the proton is a crucial challenge for QCD, and one important aspect of this is to understand how the spin of the nucleon is built up from the angular momentum of its quarks and gluons. This, it has turned out, is a very subtle and controversial issue.

The aim of this workshop is to bring together the main actors in the field of the proton spin decomposition to summarize the recent progress and discuss the remaining controversial points.

Main Topics
  • Introduction to quark and gluon angular momentum
  • Spin decompositions and sum rules
  • Gauge independence of matrix elements
  • Angular momentum, GPDs and TMDs
  • Angular momentum in phenomenological models
  • Angular momentum on the lattice
  • Angular momentum via TMD and GPD measurements in DIS and SIDIS
  • Angular momentum via TMD measurements in hadronic collisions

Key speakers include

Alessandro Bacchetta (Pavia University & INFN)
Les Bland (Brookhaven National Laboratory)
Matthias Burkhardt (New Mexico State University)
Xiang-Song Chen (Huazhong University)
Nicole D’Hose (IRFU/SPhN Saclay)
Charles Hyde (Old Dominion University)
Keh-Fei Liu (Kentucky University)
Barbara Pasquini (Pavia University & INFN)
Masashi Wakamatsu (Osaka University)


Mauro Anselmino (Torino University & INFN)
Elliot Leader (Imperial College)
Cédric Lorcé (IPN, Orsay and IFPA, Liège)