  Using lattice QCD, a diquark can be studied in a gauge-invariant manner by
binding it to a static quark in a heavy-light-light hadron. We compute the
simultaneous two-quark density of a diquark, including corrections for periodic
boundary conditions. We define a correlation function to isolate the intrinsic
correlations of the diquark and reduce the effects caused by the presence of
the static quark. Away from the immediate vicinity of the static quark, the
diquark has a consistent shape, with much stronger correlations seen in the
good (scalar) diquark than in the bad (vector) diquark. We present results for
m_{\pi}=293 MeV in N_f=2+1 QCD as well as m_{\pi}=940 MeV in quenched QCD, and
discuss the dependence of the spatial size on the pion mass.

High Energy Physics - Lattice