Flow fluctuations and kinetic freeze-out of identified hadrons at energies available at the CERN Super Proton Synchrotron

Abstract

We investigate the effect of flow fluctuations, incorporated in non boost-invariant blast-wave model, on kinetic freeze-out parameters of identified hadrons in low energy relativistic heavy-ion collisions. For the purpose of this study, we use the transverse momentum spectra of the identified hadrons produced in central Pb--Pb collisions, at SPS energies ranging from ${\mathrm{E}}_{\mathrm{Lab}}=20A-158A$ GeV, and analyze them within a modified non boost-invariant blast wave model. We perform simultaneous fits of the transverse momentum spectra for light hadrons (${\pi }^{-}$, $K^{\pm }$, $p$) and heavy strange hadrons ($\Lambda$, $\bar{\Lambda }$, $\varphi$, ${\Xi }^{\pm }$, ${\Omega }^{\pm }$) seperately. We also fit the transverse momentum spectra of charmonia ($J/\Psi$, ${\Psi }^{\prime }$) at ${\mathrm{E}}_{\mathrm{Lab}}=158A$ GeV. Our findings suggest that the inclusion of flow fluctuations enhances kinetic freeze-out temperature in case of light and heavy strange hadrons and reduces the corresponding transverse flow velocities. Moreover, we find that the kinetic freeze-out parameters of the charmonia at ${\mathrm{E}}_{\mathrm{Lab}}=158A$ GeV are least affected by inclusion of flow fluctuations. Based on this, we make predictions which can provide further insights on the role of flow fluctuations in relativistic heavy-ion collisions.

Comments: 11 pages, 8 figures, Accepted in Phys. Rev. C, Version to appear in the journal