Robustness of the scaled transverse-momentum correlator and the contribution of meson--baryon fluctuations at RHIC energies

The search for the QCD critical point relies on identifying non-monotonic signatures in event-by-event fluctuation observables, such as the scaled two-particle transverse-momentum correlator $C_{p_T}$. Using a microscopic transport model (UrQMD), we establish the robustness of $C_{p_T}$ against the