Wigner distributions and quark orbital angular momentum
  We discuss the quark phase-space or Wigner distributions of the nucleon which combine in a single picture all the information contained in the generalized parton distributions and the transverse-momentum dependent parton distributions. In particular, we present results for the distribution of unpolarized quarks in a longitudinally polarized nucleon obtained in a light-front constituent quark model. We show how the quark orbital angular momentum can be extracted from the Wigner distributions and compare it with alternative definitions. 
Cedric Lorce (Orsay, IPN and Orsay, LPT), Barbara Pasquini (Pavia U.   and INFN, Pavia)
hep-ph nucl-th