The first one is a direct application of a chiral Lagrangian already used to study flavor
symmetry breaking in Skyrme models. In another approach to the problem a SU (4)
symmetric Lagrangian is built and the symmetry is broken down to SU (3) by identifying
currents where heavy mesons are exchanged and suppressing those. Unitarization in
coupled channels leads to dynamical generation of resonances in both models, in particular …