Poincar\'e-covariant analysis of heavy-quark baryons
Abstract
We use a symmetry-preserving truncation of meson and baryon bound-state equations in quantum field theory in order to develop a unified description of systems constituted from light- and heavy-quarks. In particular, we compute the spectrum and leptonic decay constants of ground-state pseudoscalar- and vector-mesons: q q, Q Q, with q,q=u,d,s and Q,Q = c,b; and the masses of JP=3/2+ baryons and their first positive-parity excitations, including those containing one or more heavy quarks. This Poincar\'e-covariant analysis predicts that such baryons have a complicated angular momentum structure. For instance, the ground states are all primarily S-wave in character, but each possesses P-, D- and F-wave components, with the P-wave fraction being large in the qqq states; and the first positive-parity excitation in each channel has a large D-wave component, which grows with increasing current-quark mass, but also exhibits features consistent with a radial excitation. The configuration space extent of all such baryons decreases as the mass of the valence-quark constituents increases.