Jet-by-jet fluctuations of the energy-energy correlator: hadronization, decays, and medium effects
Year: 2026
Type: preprint
Abstract: Energy correlators probe how the strong interaction shapes the energy distribution within jets. Here, we study the jet-by-jet fluctuations of the energy-energy correlator (EEC). Each jet's EEC is described by a vector of densities in angular shells. Using an ensemble of these vectors, we construct the covariance matrix $C$ and Pearson correlation matrix $R$ to quantify fluctuation amplitudes and correlations between angular shells. Reconstructed jets in CMS Open Data at $\sqrt{s}=7$ TeV show positive correlations between nearby outer-angle bins and negative correlations between separated angular regions. We compare PYTHIA jets at the parton, undecayed-hadron, and final-particle stages to identify correlations already present in the shower and study how hadronization and decays reshape the angular fluctuations. PYTHIA is then coupled to linear Boltzmann transport (LBT) to study medium effects on jet-by-jet EEC fluctuations and their angular correlations. These results open a route to probing the stochastic evolution of QCD jets through jet-by-jet EEC fluctuations.
Source: arXiv (Cornell University)
Author: Zhang, Jingyu
Institution: Fudan University
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7172445101