The properties of two-particle bound states have been investigated within a relativistic quantum-field model based on the analytically confined propagators of the constituents. The spectra of quark-antiquark and two-gluon stable states are defined by master equations similar to the ladder Bethe–Salpeter equation. The conventional meson spectrum has been estimated with reasonable accuracy in a wide range of mass (from hundreds MeV up to 9.5 GeV) by introducing a minimal set of model parameters. An independent and analytic estimate is obtained for the lowest glueball mass, and we found it around ~ 1700±50 MeV . We also estimate the strong effective charge αs in the low-energy region (below ~2 GeV) by exploiting the meson spectrum. In doing so, we found a new and specific infrared-finite behavior. Particularly, an infrared fixed point is extracted . A new insight into the problem of generating the hadron mass has been provided by using the underlying principle of the compositeness condition. This allows one to express the Fermi coupling (G) as a function of meson mass М, while the Yukawa coupling (g) of the meson-quark interaction is defined by other model parameters. Both equations allow to provide an interpretation of the meson field as the bound state of its constituent fermions (quarks). We evaluate and vary the values of the masses in such a way to obtain a smooth behavior for the resulting dependence G(M). The mass spectrum obtained in this manner was found to be in good agreement with the experimental data . We also compared the behavior of the obtained G(M) with the strong QCD coupling αs calculated in a QCD-inspired approach .
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 G. Ganbold, EPJ (Web of Conf) 138, (2017) 04004.