Dynamical Fluctuations in Baryon--Meson Ratios

Abstract

The event-by-event dynamical fluctuations in kaon-to-proton and proton-to-pion ratios have been studied in dependence on center--of--mass energies of nucleon--nucleon collisions $\sqrt{s}$. Based on changing phase space volume which apparently is the consequence of phase transition from hadrons to quark--gluon plasma at large $\sqrt{s}$, the single--particle distribution function $f$ is assumed to be rather modified. Varying $f$ and phase space volume are implemented in the grand--canonical partition function, especially at $\sqrt{s}>17$ GeV, so that hadron resonance gas model, when taking into account the experimental acceptance ${\cal A}$ and quark phase space occupation factor $\gamma$, turns to be able to reproduce the dynamical fluctuations in $(K^++K^-)/(p+\overline{p})$ and $(p+\overline{p})/(\pi^++\pi^-)$ ratios over the entire range of $\sqrt{s}$.