2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/178808We evaluate in perturbative QCD, up to order $α_s^4$, the mass of the $B_c$. We use the so-called 1S-mass in order to improve the convergence of the perturbative series. Our result is $E(B_c)_{pert} = 6326^{+29}_{-9}$ MeV. Non-perturbative effects are discussed. A comparison with potential models seems to be consistent with non-perturbative contributions of the order $ - (40÷100)$ MeV.14 pages, revtex, 2 figures, minor changes, discussion on the non-perturbative corrections added, final version to appear in Phys. Rev. DHigh Energy Physics - PhenomenologyHigh Energy Physics - Experimenttext