Study of kinetic freeze-out parameters as function of rapidity in pp collisions at CERN SPS energies

TL;DR

This study investigates how kinetic freeze-out parameters like temperature, flow velocity, and volume vary with rapidity and energy in proton-proton collisions at CERN SPS, revealing dependencies on mass, energy, and rapidity.

Contribution

It applies the blast wave model with Boltzmann Gibbs statistics to analyze experimental data across different rapidities and energies, providing new insights into freeze-out parameter behaviors.

Findings

Kinetic freeze-out temperature depends on rapidity and energy.

Transverse flow velocity is independent of rapidity and energy.

Kinetic freeze-out volume depends on energy but not on rapidity.

Abstract

We used the blast wave model with Boltzmann Gibbs statistics and analyzed the experimental data measured by NA61/SHINE Collaboration in inelastic (INEL) proton-proton collisions at different rapidity slices at different center-of-mass energies. The particles used in this study are pion, kaon, proton and anti-proton. We extracted kinetic freeze-out temperature, transverse flow velocity and kinetic freeze-out volume from the transverse momentum spectra of the particles. We observed that the kinetic freeze-out temperature is rapidity and energy dependent, while transverse flow velocity does not depend on them. Furthermore, we observed that the kinetic freeze-out volume is energy dependent but it remains constant with changing the rapidity. We also observed that all these three parameters are mass dependent. In addition, with the increase of mass, the kinetic freeze-out temperature increases, and the transverse flow velocity as well as kinetic freeze-out volume decreases.