Heavy hadrons in a chiral-diquark picture

A chiral effective model including scalar, pseudoscalar, axial-vector, and vector diquarks is reviewed. The resulting diquark mass formulas can describe the relationship between the diquark masses and spontaneous chiral symmetry breaking or the $U(1)_A$ anomaly effect. Based on the two-body picture with one heavy quark and one light diquark for singly heavy baryons, we discuss the baryon spectra, decay widths, and their dependence on chiral symmetry restoration.