Nonlinear Regge Trajectories and Saturation of the Hagedorn Spectrum

We argue that two seemingly different phenomena, namely the well-known saturation of the Hagedorn exponential distribution and the less familiar saturation of Regge trajectories at resonance masses m≈ 2-2.5 GeV are related and have the same origin: quark deconfinement. We show that the slope of the real part of non-linear Regge trajectories determines the prefactor f(m) in Hagedorn's resonance mass density distribution ρ(m). While the Hagedorn distribution comes from statistics, Regge trajectories contain dynamics.