Lévy-stable pion emission sources in Au+Au collisions at √(sNN)=200 GeV from the vHLLE+SMASH hybrid model
Abstract
Revealing the space-time evolution of the quark-gluon plasma created in heavy-ion collisions is a central challenge, as this information is encoded in the properties of particles emitted at freeze-out. We reconstruct the pion emission source in Au+Au collisions at sqrt(s_NN) = 200 GeV (0-5% centrality), simulated with the vHLLE+SMASH hybrid framework, which combines a Glauber Monte Carlo initial state, (3+1)-dimensional viscous hydrodynamics, and a hadronic afterburner describing resonance decays and hadronic rescattering. Hanbury Brown-Twiss (HBT) interferometry is used to characterize identical-pion pair sources, which can also be reconstructed directly from the last scattering points of final-state particles in simulations. The projected pair-separation distributions in the Bertsch-Pratt out, side, and long directions are analyzed using a three-dimensional Levy-stable parameterization. Over the investigated fit range, extending to approximately 100 fm, a single Levy-stable function provides a satisfactory description of the distributions. The extracted Levy index, alpha approximately 1.5-1.6, is below the Gaussian value of 2 and increases slowly with transverse mass mT. At larger pair separations, the total source deviates from the fitted distribution, consistent with a halo contribution from long-lived resonance decays. Short-lived resonance decays and hadronic rescattering may contribute to the non-Gaussian shape through the Levy-walk phenomenon. The HBT radii Rout, Rside, and Rlong decrease with mT, qualitatively consistent with collective expansion. These results demonstrate the utility of Levy-stable femtoscopy for connecting hadronic-stage dynamics in hybrid simulations with experimentally accessible observables.
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BibTeX
@misc{abdelrazik2026lévystable,
title = {{Lévy-stable pion emission sources in Au+Au collisions at $\sqrts_\rm NN=200$ GeV from the vHLLE+SMASH hybrid model}},
author = {Zeinab A. Abdelrazik and Máté Csanád},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.34612},
eprint = {2610.34612},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.34612},
}
RIS
TY - UNPB
TI - Lévy-stable pion emission sources in Au+Au collisions at √(s_NN)=200 GeV from the vHLLE+SMASH hybrid model
AU - Zeinab A. Abdelrazik
AU - Máté Csanád
PY - 2026
DA - 2026/10/25
PB - arXiv
DO - 10.48550/arxiv.2610.34612
UR - https://arxiv.org/abs/2610.34612
AB - Revealing the space-time evolution of the quark-gluon plasma created in heavy-ion collisions is a central challenge, as this information is encoded in the properties of particles emitted at freeze-out. We reconstruct the pion emission source in Au+Au collisions at sqrt(s_NN) = 200 GeV (0-5% centrality), simulated with the vHLLE+SMASH hybrid framework, which combines a Glauber Monte Carlo initial state, (3+1)-dimensional viscous hydrodynamics, and a hadronic afterburner describing resonance decays and hadronic rescattering. Hanbury Brown-Twiss (HBT) interferometry is used to characterize identical-pion pair sources, which can also be reconstructed directly from the last scattering points of final-state particles in simulations. The projected pair-separation distributions in the Bertsch-Pratt out, side, and long directions are analyzed using a three-dimensional Levy-stable parameterization. Over the investigated fit range, extending to approximately 100 fm, a single Levy-stable function provides a satisfactory description of the distributions. The extracted Levy index, alpha approximately 1.5-1.6, is below the Gaussian value of 2 and increases slowly with transverse mass mT. At larger pair separations, the total source deviates from the fitted distribution, consistent with a halo contribution from long-lived resonance decays. Short-lived resonance decays and hadronic rescattering may contribute to the non-Gaussian shape through the Levy-walk phenomenon. The HBT radii Rout, Rside, and Rlong decrease with mT, qualitatively consistent with collective expansion. These results demonstrate the utility of Levy-stable femtoscopy for connecting hadronic-stage dynamics in hybrid simulations with experimentally accessible observables.
ER -