Calculation of the quarkonium spectrum and m_b, m_c to order α_s⁴

We include two loop, relativistic one loop and second order relativistic tree level corrections, plus leading nonperturbative contributions, to obtain a calculation of the lower states in the heavy quarkonium spectrum correct up to, and including, O(α_s⁴) and leading Λ⁴/m⁴ terms. This allows us, in particular, to obtain a model-independent determination of the pole masses of the b,c quarks, m_b=5015_-70⁺¹¹⁰MeV, m_c=1884_-133⁺²²²MeV, to which correspond the MS̅ masses m_b(m_b²)=4453_-32⁺⁵⁰MeV, m_c(m_c²)=1547_-102⁺¹⁶⁹MeV. The decay Γ(Υ⃗e⁺e^-) is found to be in agreement with experiment, Γ(Υ⃗e⁺e^-)=1.135_-0.29^+0.27keV (expt.=1.320±0.04keV), and the hyperfine splitting is predicted to be M(Υ)-M(η)=48.5_-12.2^+15.7MeV.