Two-pion source analysis in small to large systems at SPS energies
Abstract
Over the past decade, femtoscopic measurements using Lévy-stable source functions have been carried out in collision systems ranging from small to large at SPS, RHIC, and LHC energies. In recent years, these have been accompanied by a number of phenomenological studies of the same systems and energies. We contribute to this line of work by investigating the shape of two-pion pair-source distributions in central 7Be+9Be and 129Xe+139La collisions simulated with the UrQMD model in cascade mode. To make the comparison with measurements meaningful, kinematic selections similar to the experimental ones are applied to the simulated events and particles. One-dimensional Lévy fits are performed, and the resulting source parameters are studied as functions of pair transverse mass, collision energy, and system size. We find that the simulated sources are well described by Lévy distributions in all systems considered, which offers a common phenomenological picture of the space-time structure of pion emission. Finally, we compare our findings with results from an intermediate system, Ar+Sc. The results serve as a purely hadronic reference for past and upcoming femtoscopic measurements of the NA61/SHINE experiment.
Related
- Pion emission source shape in UrQMD Au + Au collisions at STAR energies
- Dynamical Coulomb effects on charged-pion HBT-radius splitting in central Au+Au collisions at few-GeV energies
- Dynamical Coulomb effects on charged-pion HBT-radius splitting in central Au+Au collisions at few-GeV energies
- A large size of the pion-like excitations in the stringy fluid above Tch is model independent and required by current algebra
- Constraints on pion parton distributions at small x from leading-neutron electroproduction data
BibTeX
@misc{porfy2026twopion,
title = {{Two-pion source analysis in small to large systems at SPS energies}},
author = {Barnabás Pórfy and Zsombor Marcell Rácz},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.16786},
eprint = {2610.16786},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.16786},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Two-pion source analysis in small to large systems at SPS energies
AU - Barnabás Pórfy
AU - Zsombor Marcell Rácz
PY - 2026
DA - 2026/10/12
PB - arXiv
DO - 10.48550/arxiv.2610.16786
UR - https://arxiv.org/abs/2610.16786
AB - Over the past decade, femtoscopic measurements using Lévy-stable source functions have been carried out in collision systems ranging from small to large at SPS, RHIC, and LHC energies. In recent years, these have been accompanied by a number of phenomenological studies of the same systems and energies. We contribute to this line of work by investigating the shape of two-pion pair-source distributions in central ^7Be+^9Be and ^129Xe+^139La collisions simulated with the UrQMD model in cascade mode. To make the comparison with measurements meaningful, kinematic selections similar to the experimental ones are applied to the simulated events and particles. One-dimensional Lévy fits are performed, and the resulting source parameters are studied as functions of pair transverse mass, collision energy, and system size. We find that the simulated sources are well described by Lévy distributions in all systems considered, which offers a common phenomenological picture of the space-time structure of pion emission. Finally, we compare our findings with results from an intermediate system, Ar+Sc. The results serve as a purely hadronic reference for past and upcoming femtoscopic measurements of the NA61/SHINE experiment.
ER -