Statistical description of the proton spin with a large gluon helicity   distribution
  The quantum statistical parton distributions approach proposed more than one decade ago is revisited by considering a larger set of recent and accurate Deep Inelastic Scattering (DIS) experimental results. It enables us to improve the description of the data by means of a new determination of the parton distributions. We will see that a large gluon polarization emerges, giving a significant contribution to the proton spin. 
Claude Bourrely and Jacques Soffer
hep-ph