Quark-diquark models and baryonic fluctuations in QCD

Abstract: We study the baryonic fluctuations of electric charge, baryon number and strangeness, by considering a realization of the Hadron Resonance Gas model in the light flavor sector of QCD. We elaborate on the idea that the susceptibilities can be saturated with excited baryonic states with a quark-diquark structure with a linearly confining interaction identical up to a constant to the quark-antiquark potential, $$V_{qD}^\prime(r) = V_{q{\bar q}}<sup>\prime(r)$$. We obtain an overall good agreement with the spectrum obtained with other quark models and with lattice data for the fluctuations.