Can the colour hyperfine interaction explain¹P₁data?

Abstract

The recent experimental data on 1 1P1 states of cc and bb systems are analysed for a spin independent potential consisting of a short-range colour-Coulomb potential V(r) and long-range confining interactions (linear, power law or harmonic) which are assumed to be scalar-vector admixtures (Vv(r)+Vs(r)). The spin dependent potential is obtained by the reduction of the Bethe-Salpeter kernel into the Breit interaction. It is observed that the difference between the centre of gravity (COG) of three 3PJ levels and the 1P1 level is nonzero for both the cc and bb systems, as they depend on both V(r) and Vv(r). It is found that the recent 1P1 data on cc and bb can now be reconciled with a flavour independent potential model for quarkonium.