Bridging Vacuum and Dense QCD with Jet and Event Shape from the Electron-Positron Alliance

23 Jun 2026, 11:40
20m
Buttrick 101

Buttrick 101

Session helpers - Sharelle Yazzie and Jenn James

Speaker

Yen-Jie Lee (Massachusetts Inst. of Technology (US))

Description

High-energy nuclear collisions reveal the QCD radiation and hadronization in the most complex many-body environment accessible in the laboratory. To interpret these phenomena, it is essential to establish a precise understanding of the corresponding vacuum dynamics. Electron-positron annihilation provides a uniquely clean setting where the initial state is color neutral and free of hadronic structure, allowing final-state QCD evolution to be studied with minimal ambiguity. We present recent new measurements from the Electron-Positron Alliance aimed at building precision vacuum references for jet formation, energy flow, and hadronization. This talk includes measurements of identified-particle production, such as the K/pi ratio, energy-energy correlators, jet, and jet substructure observables. It also includes an investigation of an agentic AI-based method for the event thrust analysis. These observables probe complementary aspects of QCD final states, from inclusive energy redistribution and flavor-dependent hadronization to angular correlations, jet geometry, and the scale dependence of reconstructed jets. Electron-positron data can serve as a bridge between vacuum QCD, event-generator modeling, and measurements in increasingly complex collision systems. Comparisons from e⁺e⁻ to pp, and ultimately to heavy-ion collisions, can help isolate which features arise from universal vacuum showering and hadronization, and which reflect initial-state structure, underlying event activity, or genuine medium-induced modification.

Is this an experimental talk? Yes
Is this on behalf of a collaboration? No
Are you willing to present as a poster if it is not selected for oral presentation? No

Authors

Electron Positron Alliance Yen-Jie Lee (Massachusetts Inst. of Technology (US)) Anthony Badea (University of Chicago (US)) Yi Chen (Vanderbilt University (US)) Yu-Chen (Janice) Chen (Massachusetts Institute of Technology)

Co-authors

Hannah Bossi (Massachusetts Inst. of Technology (US)) Jingyu Zhang (Vanderbilt University (US)) Mysha Jahin Khan (Vanderbilt University (US))

Presentation materials