New properties of z-scaling: flavor independence and saturation at low z

Abstract

Experimental data on inclusive cross sections of particles produced in high energy proton-(anti)proton collisions at ISR, RHIC, and Tevatron are analyzed in the framework of $z$-scaling. New features of the scaling function $\psi(z)$ are established. These are flavor independence of $\psi(z)$ including particles with heavy flavor content and saturation at low $z$. The flavor independence means that the shape of the scaling function $\psi(z)$ is the same for different hadron species. The saturation corresponds to flattening of $\psi(z)$ for $z<0.1$. Relations of model parameters used in data $z$-presentation with some thermodynamical quantities (entropy, specific heat, temperature) are discussed. It is shown that behavior of the particle spectra at low $z$ is controlled by a parameter $c$ interpreted as a specific heat of the created medium associated with production of the inclusive particle. The saturation regime of $\psi(z)$ observed at low $z$ is assumed to be preferable in searching for phase transitions of hadron matter and for study of non-perturbative QCD in high energy proton-(anti)proton collisions at U70, RHIC, Tevatron, and LHC.