Several crucial problems in evaluating spectra of baryons with two heavy quarks

The spectra of baryons which include two heavy quarks and one light quark c an be treated as a two- body system,where two heavy quarks constitute a bos onic diquark. We derive the effective potential between the light quark and the heavy diquark. In this work we have discussed several serious problems : (1) the operator ordering, (2) the errors caused by the non - relativisti c expansion, (3) spin spin coupling and (4) the mixing between baryon state s with scalar - diquark and Vector - diquark.