  We analyze hadron as well as quark and diquark correlation functions in
Landau gauge in order to extract information on the spin dependence of the
quark-quark interaction. We find evidence that the N-Delta mass splitting can
be attributed to the spin dependence of the interaction between quarks in a
colour anti-triplet state with spin 0 and 1, respectively. The lightest
excitations are observed in the S=0 channel. However, no evidence for a deeply
bound diquark state is found.
