The Quark-Gluon Plasma through Energy Correlators

Introduction

The Quark-Gluon Plasma (QGP) created in high-energy collisions of heavy nuclei at the Large Hadron Collider (LHC) is an exotic state of matter made of deconfined quarks and gluons. It behaves as a strongly-coupled fluid, with no discernible microscopic particle-like dynamics. Understanding how this strongly-coupled liquid emerges from matter which, at very short distances, is made of weakly-coupled partons stands as one of the paramount challenges in heavy-ion physics for the coming decade.

Research Objectives

To address this fundamental question, we must probe the QGP at varying resolution scales. The QGPthroughEECs project proposes an innovative approach to multi-scale microscopy of the QGP, based on examining the structure of the jets' energy flux deposited on the detectors. This is captured in a class of observables finding their origins in conformal field theories known as energy-energy correlators (EECs).

Methodology

N-point EECs look at the energy distribution of all combinations of N final particles within a jet as a function of their angular distances. Much like temperature correlations of the cosmic microwave background offer insights into the Universe's time evolution, the structure of EECs across their angular regimes gives access to the QGP dynamics at distinct length scales.

Expected Outcomes

By developing the quantum chromodynamics (QCD) first-principles framework for heavy-ion jets’ EECs and computing specific EECs sensitive to elusive QGP phenomena, this project aims to answer several long-standing questions about the QGP inner dynamics. These include:

1. Quantifying the role of color decoherence.
2. Unveiling how the QGP modifies the QCD dead-cone effect.
3. Establishing compelling evidence of medium response.
4. Determining the length scale at which the description of the QGP in terms of quasiparticles becomes valid.

Expertise

As the person who pioneered the application of EECs to heavy-ion physics and with broad expertise in jet quenching theoretical calculations, the PI is in a unique position to achieve these ambitious goals.