The spectroscopy of light mesons

A review is given of the most recent experimental data on light meson resonances together with a phenomenological analysis incorporating all the basic ideas of QCD. The following topics are discussed in greater detail: (1) the scalar meson problem; (2) the axial meson problem; (3) spin-spin and spin-orbit splitting in meson multiplets; (4) SU$^f_3$ and OZI (Okubo–Zweig–Iizuka) breaking in meson spectra and decays; (5) SU$^f_3$ breaking in Regge trajectories and in radial excitations; (6) quark mixing in isoscalar mesons ($\eta$-$\eta'$, $\omega$-$\varphi$, $f$-$f'$); (7) experimental determinations of the $\eta$-$\eta'$ mixing angle, and (8) radiative decays of vector and pseudoscalar mesons.