Spin and Resonant States in QCD

Abstract

I make the case that the nucleon excitations do not exist as isolated higher spin states but are fully absorbed by (K/2,K/2)*[(1/2,0)+ (0,1/2)] multiplets taking their origin from the rotational and vibrational excitations of an underlying quark--diquark string. The Δ(1232) spectrum presents itself as the exact replica (up to Δ(1600)) of the nucleon spectrum with the K- clusters being shifted upward by about 200 MeV. QCD inspired arguments support legitimacy of the quark-diquark string. The above K multiplets can be mapped (up to form-factors) onto Lorentz group representation spaces of the type ψ_μ_1...μ_K, thus guaranteeing covariant description of resonant states. The quantum ψ_μ_1...μ_K states are of multiple spins at rest, and of undetermined spins elsewhere.