Small momentum transfer elastic pion-proton cross-section at high energies is
calculated assuming the proton is composed of two constituents, a quark and a
diquark. We find that it is possible to fit very precisely the data when (i)
the pion acts as a single entity (no constituent quark structure) and (ii) the
diquark is rather large, comparable to the size of the proton.Comment: 9 pages, 4 figure
