The role of spin polarization in event-by-event fluctuations
Abstract
The event-by-event initial state fluctuations constitute a critical physical quantity for understanding the dynamics of high-energy heavy-ion collisions. Due to the extremely limited available experimental data of such fluctuations, it is difficult to constrain or direct the characterization of the underlying initial state properties. This work constrains the correlation function between the initial eccentricity and the asymmetry by employing a parton distribution function that incorporates spin polarization induced by thermal vorticity and thermal shear. Based on the kinetic theory calculations, we found that the asymmetry fluctuations considering spin polarization have a significant splitting effect compared to those without spin polarization. These splitting exhibit pronounced system size and energy dependence. Moreover, the ratios of correlation function display similar system size and energy dependence--particularly in the low-temperature regime (T ≲ 0.12 GeV). These results suggest that spin polarization may serve as a useful constraint method for the event-by-event initial state fluctuations of heavy-ion collisions.
Related
- Event-by-event net-charge fluctuations in pp, OO, Ne-Ne, and Pb-Pb collisions with ALICE at the LHC
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- Measurements of local polarization of Λ hyperons with event shape engineering in Au+Au collisions at RHIC-STAR
- Anisotropic chromo-field fluctuations and spin alignment of quarkonia
BibTeX
@misc{he2026role,
title = {{The role of spin polarization in event-by-event fluctuations}},
author = {Xiao-Ying He and Li-Juan Zhou and Li-Xin Yang and Qian-Qian Du and De-Xian Wei},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.41386},
eprint = {2610.41386},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.41386},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - The role of spin polarization in event-by-event fluctuations
AU - Xiao-Ying He
AU - Li-Juan Zhou
AU - Li-Xin Yang
AU - Qian-Qian Du
AU - De-Xian Wei
PY - 2026
DA - 2026/10/30
PB - arXiv
DO - 10.48550/arxiv.2610.41386
UR - https://arxiv.org/abs/2610.41386
AB - The event-by-event initial state fluctuations constitute a critical physical quantity for understanding the dynamics of high-energy heavy-ion collisions. Due to the extremely limited available experimental data of such fluctuations, it is difficult to constrain or direct the characterization of the underlying initial state properties. This work constrains the correlation function between the initial eccentricity and the asymmetry by employing a parton distribution function that incorporates spin polarization induced by thermal vorticity and thermal shear. Based on the kinetic theory calculations, we found that the asymmetry fluctuations considering spin polarization have a significant splitting effect compared to those without spin polarization. These splitting exhibit pronounced system size and energy dependence. Moreover, the ratios of correlation function display similar system size and energy dependence--particularly in the low-temperature regime (T ≲ 0.12 GeV). These results suggest that spin polarization may serve as a useful constraint method for the event-by-event initial state fluctuations of heavy-ion collisions.
ER -