On the study of the QCD string model and its application to meson spectroscopy

The meson spectroscopy is studied in the framework of the QCD string model. The mesons are composed of spinless quarks which move relativistically. We show that the QCD string model reproduces the straight line Regge trajectories and exibit the correct string slopes for both light-light and heavy-light mesons. We also present the exact numerical solution and the analytic approximation solution of the QCD string equations for the light-light mesons under the deep radial limit. We demonstrate that the QCD string model describes the universal relations for the light-light and heavy-light meson spectroscopies correctly from the comparison of the exact numerical solutions of the QCD string model for both light-light and heavy-light mesons.