Charmonia in a contact interaction

For the flavor-singlet heavy quark system of charmonia, we compute the masses of the ground state mesons in four different channels: pseudoscalar [eta(c)(1S)], vector [ J/psi (1S)], scalar [chi(c0)(1P)] and axial vector [chi(c1) (1P)], as well as the weak decay constants of the eta(c)(1S) and J/psi(1S) and the charge radius of eta(c)(1S). The framework for this analysis is provided by a symmetry-preserving Schwinger-Dyson equation ( SDE) treatment of a vector x vector contact interaction. The results found for the meson masses and the weak decay constants, for the spin-spin combinations studied, are in fairly good agreement with experimental data and earlier model calculations based upon Schwinger-Dyson and Bethe-Salpeter equations involving sophisticated interaction kernels. The charge radius of eta c(1S) is consistent with the results from refined SDE studies and lattice quantum chromodynamics.