Exploring QCD Matter through Energy Correlators of Soft Hadrons
Abstract
We propose energy-energy correlators (EECs) of soft hadrons and their azimuthal harmonics as new soft observables to probe the collective flow and correlations beyond flow for large and small systems created in high energy nuclear collisions. We separate the soft EEC into a disconnected contribution determined by the mean energy flow and a connected contribution encoding correlations beyond it. Viscous hydrodynamic simulations demonstrate that the soft EEC of a fluid system is governed by the disconnected contribution, while its elliptic and triangular harmonics respond to the initial geometry and shear viscosity as traditional flow harmonics do. Comparisons between iEBE-VISHNU and PYTHIA for p+p, O+O, and Pb+Pb collisions show that the disconnected contribution dominates at large angles in all systems, whereas connected correlations beyond the mean energy flow grow toward small angles and small systems, most strongly for the harmonics. Soft EECs thus provide a unique window into collective flow and correlations beyond it across collision systems.
Related
- Exploring Anomaly-Free Dark Photon Models Through Solar Neutrino-Electron Scattering in Ton-Scale Dark Matter Detectors
- Transverse-spin dependent energy-energy correlators in proton-proton collisions within the dihadron fragmentation framework
- Gluonic nucleon energy correlators and fracture functions for Color Glass Condensate
- Transverse-spin dependent energy-energy correlators in proton-proton collisions within the dihadron fragmentation framework
- Energy-energy correlators and color decoherence from a generating functional
BibTeX
@misc{peng2026exploring,
title = {{Exploring QCD Matter through Energy Correlators of Soft Hadrons}},
author = {Yiyang Peng and João Barata and Andrey V. Sadofyev and Huichao Song},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.22477},
eprint = {2610.22477},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.22477},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Exploring QCD Matter through Energy Correlators of Soft Hadrons
AU - Yiyang Peng
AU - João Barata
AU - Andrey V. Sadofyev
AU - Huichao Song
PY - 2026
DA - 2026/10/15
PB - arXiv
DO - 10.48550/arxiv.2610.22477
UR - https://arxiv.org/abs/2610.22477
AB - We propose energy-energy correlators (EECs) of soft hadrons and their azimuthal harmonics as new soft observables to probe the collective flow and correlations beyond flow for large and small systems created in high energy nuclear collisions. We separate the soft EEC into a disconnected contribution determined by the mean energy flow and a connected contribution encoding correlations beyond it. Viscous hydrodynamic simulations demonstrate that the soft EEC of a fluid system is governed by the disconnected contribution, while its elliptic and triangular harmonics respond to the initial geometry and shear viscosity as traditional flow harmonics do. Comparisons between iEBE-VISHNU and PYTHIA for p+p, O+O, and Pb+Pb collisions show that the disconnected contribution dominates at large angles in all systems, whereas connected correlations beyond the mean energy flow grow toward small angles and small systems, most strongly for the harmonics. Soft EECs thus provide a unique window into collective flow and correlations beyond it across collision systems.
ER -