The international collaboration ALICE (“A Large Ion Collider Experiment”), of which the eponymous research group of the IP2I in Lyon is a member, aims to study nuclear matter in a state of extremely high temperature, where the deconfinement of hadrons (including protons and neutrons) into plasma of quarks and gluons takes place.
Matter is made up of atoms, themselves made up of electrons surrounding a nucleus of protons and neutrons, the latter being formed of quarks, linked by gluons. No quark or gluon has ever been observed in isolation: they appear to be permanently bonded together and confined in composite particles. At temperatures 100,000 times higher than those at the centre of the Sun, they deconform to form a plasma, which would have existed a few microseconds after the Big Bang. This plasma is predicted by the fundamental theory of strong interaction, Quantum Chromodynamics (QCD), and its study allows us to understand the ultimate organization of matter subject to strong interaction and the very first moments of the universe.
The LHC collides lead ions to recreate conditions similar to those immediately after the Big Bang and form this quark and gluon plasma. For this infinitely small study, a huge detector has been built at the LHC. It is capable of measuring the particles emitted by the plasma as it expands and cools.
Our group has been involved in this construction and in obtaining major results in this field of physics.
The activities of the ALICE group of the IP2I of Lyon are twofold:
- the analysis of data collected in proton-proton, proton-nucleus and nucleus-nucleus collisions at the CERN LHC
- participation in the construction and operation of the forward vertex trajectograph, the Muon Forward Tracker
Analysis of data collected in proton-proton, proton-nucleus and nucleus-nucleus collisions at the CERN LHC
The physics analyses of the ALICE experiment carried out in the Lyon groups cover a wide range of subjects, from the light quark sector u, d, s with the study of the forward production of low mass vector mesons 
and 
in the dimuonic decay channel, to the heavy quarks sector c and b, with the study of the production of the quarkonium states of the 
and 
families. This analytical work has already led to a number of remarkable results, notably through the study of collective phenomena characterizing the evolution of the and mesons, namely the appearance of kinematic correlations between the meson and light hadrons in high multiplicity proton-Pb collisions, and the observation of elliptical flow of the 
meson compatible with zero in Pb-Pb collisions (behavior different from all the other particles studied).
Participation in the construction and operation of the forward vertex trajectograph, the Muon Forward Tracker
The group is also responsible for the construction and operation of the vertex forward trajectograph, the Muon Forward Tracker (MFT), one of the first applications in high energy physics of CMOS silicon pixel sensor technology. The MFT, which will be integrated into the ALICE detector starting with Run3 of the LHC (2021), is designed to enable precise measurement of the details of the vertex region for forward-produced particles, especially muons, whose different topologies and production processes can be studied.
NON-PERMANENTS:
- DOCTORANTS / DOCTORAL STUDENTS:
- P. Achard, O. Adriani, M. Aguilar-Benitez, J. Alcaraz, G. Alemanni, et al.. Measurement of exclusive
production in mid-virtuality two-photon interactions and study of the 
process at LEP. Physics Letters B, 2005, 615, pp.19-30. ⟨10.1016/j.physletb.2005.04.011⟩. ⟨in2p3-00024138⟩ - H.K. Wöhri, R. Arnaldi, K. Banicz, J. Buytaert, J. Castor, et al.. Low mass dimuon production in proton-nucleus collisions with the NA60 apparatus. International Conference on Hard and Electromagnetic Probes of High Energy Nuclear Collisions - Hard Probes 2004, Nov 2004, Ericeira, Portugal. pp.407-413, ⟨10.1140/epjc/s2005-02206-1⟩. ⟨in2p3-00024262⟩
- X. Artru. Analogy between free electron laser and channeling by crystal planes. International Workshop on Charged and Neutral Particles Channeling Phenomena "Channeling 2004", Nov 2004, Rome, Italy. 597404 (7 p.). ⟨in2p3-00023911⟩
- X. Artru, K. Beloborodov, R. Chehab, M. Chevallier, V. Shary, et al.. High intensity positron sources using channeling in crystals. International Workshop on Charged and Neutral Particles Channeling Phenomena "Channeling 2004", Nov 2004, Rome, Italy. 59740E (6 p.). ⟨in2p3-00024585⟩
- H. Ohnishi, R. Arnaldi, R. Averbeck, K. Banicz, K. Borer, et al.. J/
production in indium–indium collisions. 8th International Conference on Strangeness in Quark Matter (SQM2004), Sep 2004, Cape Town, South Africa. pp.S1209-S1212, ⟨10.1088/0954-3899/31/6/089⟩. ⟨in2p3-00024621⟩ - S. Damjanovic, R. Arnaldi, R. Averbeck, K. Banicz, K. Borer, et al.. First results from NA60 on low mass muon pair production in In-In collisions at 158 GeV/nucleon. 8th International Conference On Strangeness In Quark Matter (SQM2004), Sep 2004, Cape Town, South Africa. pp.S903-S910, ⟨10.1088/0954-3899/31/6/034⟩. ⟨in2p3-00024354⟩
- X. Artru. Impact parameter profile of synchrotron radiation. Nato Worskhop on Radiation by Relativistic Electrons in Periodic Structures, Aug 2004, Nor-Hamberd, Armenia. pp.387-398. ⟨in2p3-00023910⟩
- K. Borer, W. M. Chen, Z. Li, C. Cicalo, A. de Falco, et al.. First results of the NA60 experiment at the CERN SPS. 18th Nuclear Physics Division Conference of the EPS. Phase Transitions in Strongly Interacting Matter., Aug 2004, Prague, Czech Republic. pp.251-256, ⟨10.1016/j.nuclphysa.2004.12.047⟩. ⟨in2p3-00024626⟩
- A. Colla, R. Arnaldi, R. Averbeck, K. Banicz, K. Borer, et al.. Study of the J/ production and suppression in In–In collisions at the CERN SPS. Workshop for Young Scientists on the Physics of Ultra-Relativistic Nucleus-Nucleus - HOT QUARKS 2004, Jul 2004, Taos Valley, New Mexico, United States. pp.S317-S323, ⟨10.1088/0954-3899/31/4/039⟩. ⟨in2p3-00024622⟩
- M. Floris, K. Borer, W. M. Chen, Z. Li, C. Cicalo, et al.. Charged particle multiplicity measurements in NA60. International Workshop on Particle Multiplicity In Relativistic Heavy Ion Collisions Focus on Multiplicity, Jun 2004, Bari, Italy. pp.55-63, ⟨10.1088/1742-6596/5/1/005⟩. ⟨in2p3-00024196⟩
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