What does the data tell us about the quark-antiquark potential?

Abstract

In view of the failure of the standard charmonium models to explain ψ-η_c and ³PJ splittings, I consider various possible modifications to these models. In particular, I show that for power-law potentials the spin forces are most likely generated through the admixture of scalar-vector-Pauli moment exchanges and that this model can be tested by measuring the ¹p₁ mass. I also show that if instantons really generate a large spin-spin force, then the ¹p₁ mass must be as low as 3250-3270 MeV.