QCD critical point, baryon number fluctuations, and final state interactions

Baryon number cumulants are important quantities to diagnose the primordial stage of heavy ion collisions. In experiments, however, proton number cumulants have been measured as substitutes. In fact, proton number fluctuations are further modified in the hadron phase and different from those of baryon number. We explore the relation between proton and nucleon number fluctuations in the final state in relativistic heavy ion collisions.