  An elementary constituent-quark (CQ) model by Mac Gregor is reviewed with
currently published data from light meson spectroscopy. It was previously shown
in the CQ model that there existed several mass quanta m = 70 MeV, B = 140 MeV
and X = 420 MeV, which were responsible for the quantization of meson yrast
levels. The existence of a 70-MeV quantum was postulated by Mac Gregor and was
shown to fit the Nambu empirical mass formula mn = (n/2)137me, n a positive
integer. The 70-MeV quantum can be derived in three different ways: 1) pure
electric coupling, 2) pure magnetic coupling, and 3) mixed electric and
magnetic charges (dyons). Schwinger first introduced dyons in a magnetic model
of matter. It is shown in this paper that recent data of new light mesons fit
into the CQ model (a pure electric model) without the introduction of magnetic
charges. However, by introducing electric and magnetic quarks (dyons) into the
CQ model, new dynamical forces can be generated by the presence of magnetic
fields internal to the quarks (dyons). The laws of angular momentum and of
energy conservation are valid in the presence of magnetic charge. With the
introduction of the Russell-Saunders coupling scheme into the CQ model, several
new meson particles are predicted to exist. The existence of the f0(560) meson
is predicted and is shown to fit current experimental data from the Particle
Data Group listing. The existence of meson partners or groupings is shown.
