Plasma Team

The primordial soup

Recreate the conditions of the Universe just after the Big Bang, when it consisted only of fundamental particles.

Quark-gluon plasma (GQP)

A state of matter in which the quarks linked by gluons (fundamental particles that form protons and neutrons, for example) are no longer confined in conventional nuclear matter’.

QGP measurement

Probing the extreme

The experimental study of GQP is quite a challenge. It involves characterizing a little-known medium formed when heavy ions collide at very high energies (~TeV/nucleon). The PQG droplet is the size of an atomic nucleus and remains for only a fraction of a second (~10^-22s). Experiments can only measure the final products of collisions. The challenge is to reconstruct the history of the collision in order to deduce the properties of the QGP (thermalization, viscosity, etc.) and the creation of the particles.

Big data on a global scale

The volume of data produced by experiments such as ALICE represents several tens of Po per year. Physics analyses are carried out on interconnected computing farms spread across the planet: the LHC computing grid.

3D camera with10¹⁰ pixels and 50.000 images/s

The cathedrals of physics

Measuring the GQP requires monumental equipment such as the ALICE experiment (16m in diameter and 25m long), alongside gigantic particle colliders such as the LHC, a ring 27 km in circumference. It took 15 years from conception to measurement of the first collisions. Constantly being improved, ALICE is scheduled to operate until 2033.

GQP study with ALICE

Subatech is currently involved in the ALICE experiment, and more specifically in the muon spectrometer coupled to the Muon Forward Tracker and the electromagnetic calorimeter. Muon measurements are used to trace the production rate of J/Psi particles (quark-antiquark pairs), the historic signature of the PQG. J/Psi particles can be traced back to the dynamics and thermalization of quarks. The calorimeter measures photon energy, enabling us to study the interaction of quarks in the plasma of quarks and gluons.

2
PhD students
3
post-doctoral fellows
10
researchers

1999 / Creations

ENGAGEMENT IN ALICE at the LHC (CERN) then STAR at RHIC

2000 / RHIC

RHIC START-UP at Brookhaven (USA).

2010 / LHC Run1

FIRST PbPb COLLISIONS AT LHC Start of GQP study with ALICE

2021 / Upgrades

ALICE UPGRADES Installation of the MFT and improvement of the muon spectrometer

Last modification on 03 November 2024at18 h 58