p States of Charmonium and the Forces that Confine Quarks

A measurement of the energy differences of the $n=2$, ³PJ states of charmonium may give significant information on the dynamics of the spin-dependent quark-antiquark (qq̄) forces, since the more rapidly these forces increase with qq̄ separation, the larger the ratios ${R}₁={[E(³P₂){-}E(³P₁)]}{[E(³P₁){-}E(³P₀)]} and {R}₂={[E(³P₁){-}E(¹P₁)]}{[E(³P₁){-}E(³P₀)]}$ become if the forces are of vector character.