Quarks, diquarks and QCD mixing in the $N^*$ resonance spectrum

Abstract

We identify a "$Λ$ selection rule" for $N^*$ resonances in the presence of QCD mixing effects. We quantify these mixing effects from existing data and predict amplitudes for exciting {\bf 20} representations in SU(6), which are forbidden in strict diquark models. By classifying Particle-Data-Group (PDG) states at N=2, we show that $γN\to KΛ$, $K^*Λ$, $KΣ$, $K^*Σ$, and $J/ψ\to \bar{p}N^*$ are ideal probes of baryon dynamics and for establishing whether strongly correlated diquarks survive for $L > 0$.