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Jet quenching for heavy-ion collisions at the LHC

Project description

A first-principle approach to jet quenching

Collisions of ultra-relativistic heavy ions in the Large Hadron Collider in Geneva and the Relativistic Heavy Ion Collider in New York form the hot, dense medium known as the quark–gluon plasma (QGP). One of the main experimental tools to characterise the QGP is the analysis of the propagation of elementary quarks and gluons through it. These elementary particles fragment into highly collimated jets that lose energy through a phenomenon known as jet quenching, whose study can help improve our understanding of the QGP behaviour. Based on recent findings suggesting that jets are sensitive to the QGP pre-equilibrium dynamics, the EU-funded JQ4LHC project plans to develop the first jet quenching bottom-up formalism based on first principles which will also enable the investigation of this early dynamics.


The characterization of the quark gluon plasma (QGP) created in heavy-ion collisions (HICs) is the main goal of heavy-ion experimental programs at the Relativistic Heavy Ion Collider (RHIC) at BNL (USA) and at the Large Hadron Collider (LHC) at CERN. Jet quenching, the modification of jets in a colored medium, is one of the most successful tools to probe the QGP. This proposal aims to provide an interpretational framework for jet quenching that maximizes the discovery potential of the current (and future) precision era of HICs.

Since the study of jets in the presence of a medium is challenging, we still lack a first-principles formalism for jets in HICs. In contrast, a wide variety of jet quenching Monte Carlos (MCs) are available, but they rely on phenomenological assumptions making difficult to interpret their outcomes. It is proposed here to develop the first jet quenching bottom-up formalism based on first principles. This will be done by generalizing from single hadrons to jets a previous implementation by the experienced researcher (ER), including different phenomena as coherence. This analytical approach will become a unique tool to describe the QGP and benchmark the mainstream MCs.

The theory of jet quenching has been developed assuming a QGP in thermal equilibrium. Recently, the ER has shown for the first time that jets in HICs are sensitive to the pre-equilibrium dynamics of the evolution. This finding paves the way for a completely novel line of research in HICs, whose ambitious goal is to access these poorly understood initial stages with jet quenching observables. This proposal will provide the foundations for such an effort by phenomenologically analyzing the possible explanations to this finding and by computing color field configurations for the initial stages in the Glasma approach.

This project will be developed at the leading institution École Polytechnique and will enhance the skills, career prospects and network of collaborators of the ER.


Net EU contribution
€ 196 707,84
91128 Palaiseau Cedex

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Ile-de-France Ile-de-France Essonne
Activity type
Higher or Secondary Education Establishments
Total cost
€ 196 707,84