Relativistic effects on meson spectra

The meson masses are considered to retain total relativistic effects for spinors instead of Fermi-Breit approximation. This necessitates a diagonalization approach instead of solutions of differential equations. Correction over Fermi-Breit form appears to be significant. For heavy quark systems agreement with experiment is found. The method will be quite useful if the quark-antiquark dynamics becomes sufficiently known. 5 tables, 32 refs. (author)