Constituent quark and diquark properties from small angle proton-proton   elastic scattering at high energies
  Small momentum transfer elastic proton-proton cross-section at high energies is calculated assuming the nucleon composed of two constituents - a quark and a diquark. A comparison to data (described very well up to -t = 2 GeV^2/c) allows to determine some properties of the constituents. While quark turns out fairly small, the diquark appears to be rather large, comparable to the size of the proton. 
A. Bialas, A. Bzdak