18-05-2018
In ultra-relativistic heavy ion collisions at CERN's LHC accelerator, a new state of matter is formed: the quark-gluon plasma (QGP). It is a kind of very dense and hot "soup" containing only the most elementary constituents of matter. A few microseconds after the Big Bang, the Universe would have passed through this state. Because of the interactions between its constituents, the QGP flows like a fluid.
25-04-2017
According to the ALICE collaboration at LHC (CERN), certain rare proton collisions have properties that are similar to those of a quark–gluon plasma. In the past, these properties had been observed for collisions of heavy nuclei only. The physicists are now confronted with a new enigma: how can a state of quark–gluon plasma emerge in a system as "small" as that generated by a collision between two protons?
30-01-2017
A team from IRFU, a member of the ALICE collaboration at CERN, has coordinated the analysis of J/ψ particles produced during lead-lead collisions at the LHC (CERN). Their results provide a solid indication of the existence of a quark–gluon plasma.
21-11-2014
Le Large Hadron Collider (LHC) au CERN a récemment mené à bien le programme de collisions de protons sur des noyaux de plomb. C’est à dessein que cette catégorie de collisions a été choisie, car elle permet d’étudier comment l’environnement nucléaire perturbe la structure interne d’un nucléon individuel donné dans le noyau de plomb.
02-12-2010
The first lead-lead collision results have been published
After almost a year collecting data from proton-proton collisions, the LHC at CERN began the injection of lead ions at the beginning of November, with the first collisions obtained on November 8. The energy in the nucleon-nucleon center of mass is 2.76 TeV, around ten times greater than that achieved previously by the RHIC in Brookhaven USA. The first results from ALICE have been made available without delay.
25-02-2010
The Phenix and Star collaborations, which include physicists from CEA-IRFU and CNRS-IN2P3, have announced major discoveries on the nature of the quark-gluon plasma. These conclusive results, which advance our understanding of nuclear material subjected to extreme conditions, shed new light on the birth of the universe. They have been published in the journal Physical Review Letters.  
23-12-2009
Monday, 23 November 2009, marked the first particle beam collision inside the large detectors of the LHC. ALICE saw its first collisions at an energy of 900 GeV, enabling it to check for correct operation of the 18 large detectors which comprise it. Since 27 November, with just a few days worth of data, the collaboration has even published an article confirming some existing measurements.
05-05-2009
At the end of March 2009, the ALICE Muon Spectrometer took cosmic rays over a period of two weeks. The ALICE group at Saclay2 was closely involved in the design, development, construction and installation of a part of the chambers of this Spectrometer3. The purpose of the cosmic ray test was to check the performance of the entire system, from acquisition to reconstruction of the data. The acquisition system readout about a million channels and the data was recorded on the computing grid.

 

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