Nucleon Momentum Decomposition in QCD
  ~Based on the gauge invariant quark canonical momentum we construct two theoretically possible decompositions of nucleon momentum to those of quarks and gluons. We predict that either 6% or 21% of nucleon momentum is carried by gluons, depending on what type of gluons are in nucleons. We clarify the existing confusions on this problem and discuss the physical implications of our result on the proton spin crisis problem. 
Y.M. Cho, Mo-Lin Ge, D.G. Pak, and Pengming Zhang
nucl-th hep-ph nucl-ex