Pion freeze-out as seen through HBT correlations in heavy ion collisions from FAIR/AGS to RHIC energies

Abstract

We perform a systematic analysis of several HBT parameters in heavy ion collisions from $E_{\mathrm{beam}}=2$ AGeV to $\sqrt{s_{\mathrm{NN}}}=200$ GeV within the UrQMD transport approach and compare the results to experimental data where available. We find that the 'lifetime' of the emission source as calculated from $\tau \sim \sqrt{R_O^2-R_S^2}$, is larger than the experimentally observed values at all investigated energies. The calculated volume of the pion source ($V_f$) is found to increase monotonously with increasing beam energy and the experimentally observed decrease of the measured $V_f$ at AGS is not seen. Finally, we calculate the mean free path ${\lambda }_f=0.5-1$ fm of pions at freeze-out and find a good description of the experimental data above the AGS energy region, supporting the suggestion of a universal kinetic decoupling criterion up to the highest RHIC energies.

11 pages, 2 figs

References in corpus (5)

• Status of Chemical Freeze-Out
• Directed and elliptic flow in heavy ion collisions from $E_{\mathrm{beam}}=90$ MeV/nucleon to $E_{c.m.}=200$ GeV/nucleon
• Transport model analysis of particle correlations in relativistic heavy ion collisions at femtometer scales
• Transport model analysis of the transverse momentum and rapidity dependence of pion interferometry at SPS energies
• Heavy-Ion Physics with ALICE

Cited by in corpus (5)

• The effect of "pre-formed" hadron potentials on the dynamics of heavy ion collisions and the HBT puzzle
• Effects of a phase transition on HBT correlations in an integrated Boltzmann+Hydrodynamics approach
• Effects of a phase transition on two-pion interferometry in heavy-ion collisions at $\sqrt{s_{\mathrm{NN}}}=2.4-7.7$ GeV
• A model comparison of resonance lifetime modifications, a soft equation of state and non-Gaussian effects on $\pi -\pi$ correlations at FAIR/AGS energies
• Transport model study of the $m_T$-scaling for $\Lambda$, K, and $\pi$ HBT-correlations