Quark-diquark string tension, excited baryonic resonances and thermal fluctuations

We study the baryonic fluctuations from second to eighth order involving electric charge, baryon number and strangeness below the quark-gluon plasma crossover and numerically known from lattice QCD calculations. By considering a particular realization of the Hadron Resonance Gas model, we provide evidence on the dominant role of quark-diquark degrees of freedom to describe excited baryonic resonances. After proving by means of suitable Polyakov loop correlators that the quark-diquark and the quark-antiquark forces coincide, $V_{\overline{q}q}\left(r\right)=V_{\overline{q}D}\left(r\right)+const$, we find that the corresponding susceptibilities can be saturated with excited baryonic states in a quark-diquark model picture. (paper)