Bottom-charmed meson spectrum from a QCD approach based on the Tamm-Dancoff approximation

The bottom-charmed meson spectrum is studied via an effective version of the Coulomb gauge QCD Hamiltonian. The Tamm-Dancoff approximation is employed to estimate the energies of the low-lying and radial-excited Bc states with quantum numbers JP=0^-,0⁺,1^-,1⁺,2⁺,2^-. In particular, we analyze the effects of incorporating an effective transverse hyperfine interaction and spin mixing. The Regge trajectories and hyperfine splitting of both S- and P-wave states are also examined. The numerical results are compared with available experimental data and the theoretical predictions of other models.