  We describe a symmetry-preserving calculation of the meson spectrum, which
combines a description of pion properties with reasonable estimates of the
masses of heavier light-quark mesons, including axial-vector states. The
kernels used in formulating the problem are essentially nonperturbative. They
incorporate effects of dynamical chiral symmetry breaking (DCSB) that were not
previously possible to express. Our analysis clarifies a causal connection
between DCSB and the splitting between vector and axial-vector mesons, and
exposes a key role played by the anomalous chromomagnetic moment of
dressed-quarks in forming the spectrum.
