We study meson and diquark bound states using the rainbow-ladder truncation
of QCD's Dyson-Schwinger equations. The infrared strength of the rainbow-ladder
kernel is described by two parameters. The ultraviolet behavior is fixed by the
one-loop renormalization group behavior of QCD, which ensures the correct
asymptotic behavior of the Bethe-Salpeter amplitudes and brings important
qualitative benefits. The diquark with the lowest mass is the scalar, followed
by the axialvector and pseudoscalar diquark. This ordering can be anticipated
from the meson sector.Comment: 14 pages, 4 figures, to appear in Few-Body System