Initial Conditions for Quark and Gluon Matter Formation at the LHC

Introduction

The central goal of heavy-ion physics at the energy frontier is to create, and study in the laboratory, Quark-Gluon Plasma (QGP), a state of matter predicted by the fundamental theory of strong interactions.

Current Understanding

Current state-of-the-art interpretation of experimental data from the LHC experiments relies on Bayesian global fits of anisotropic flow (v_n) and mean transverse momentum ([p_T]), and provided the first quantitative measures of the fundamental transport parameters (shear and bulk viscosity) of the QGP. This represents the best understanding of the QGP so far.

Challenges in Analysis

However, recent studies of the correlations between anisotropic flow and mean transverse momentum reveal that no existing Bayesian analysis can describe the new data in a consistent way because of the lack of constraints on the initial conditions, which set the stage for the subsequent dynamic evolution.

Scientific Urgency

Hence, it is scientifically urgent to significantly improve understanding about the initial conditions in the various collision types that can be probed at the world’s leading facility, the Large Hadron Collider. This improvement is necessary to extract precise properties of the QGP and its dynamic evolution as a function of temperature (time).

Methodology Development

In this ERC project, I will develop methodology for studying genuine correlations between (v_n) and ([p_T]), using a new approach, a multi-particle cumulants technique. This will give unique insights into the initial geometric conditions, shape, size, and their correlations and fluctuations.

Experimental Approach

To achieve this, I will measure on various collision systems (129Xe, 16O, and proton) during the coming LHC Run 3. These pioneering measurements, and the resulting new analyses, will decisively advance our understanding of those crucial initial conditions that are the platform upon which the analysis of the entire collision rests.

Expected Outcomes

The results of this ERC will make it possible to determine the ultra-precise QGP properties and discover the new physics that could revise our concepts of the initial conditions.