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:
- CHERCHEURS NON-PERMANENTS / NON-PERMANENT RESEARCHERS:
- M. Acciarri, O. Adriani, M. Aguilar-Benitez, S. Ahlen, J. Alcaraz, et al.. Production of Single W Bosons in
Interactions at 130 
183 GeV and Limits on Anomalous WW
Couplings. Physics Letters B, 1998, 436, pp.417-427. ⟨in2p3-00023168⟩ - M C. Abreu, J. Astruc, C. Baglin, A. Baldit, M. Bedjidian, et al.. Transverse momentum of J/
and mass continuum muon pairs produced in 
S-U collisions at 200 GeV/c per nucleon. Physics Letters B, 1998, 423, pp.207-212. ⟨10.1016/S0370-2693(98)00088-4⟩. ⟨in2p3-00005042⟩ - X. Artru, R. Kirsch, R. Chehab, B. Johnson, P. Keppler, et al.. Radiation-damage study of a monocrystalline tungsten positron converter. European Particle Accelerator Conference EPAC'98, 1998, Stockholm, Sweden. pp.1-4. ⟨in2p3-00003406⟩
- M. Acciarri, O. Adriani, M. Aguilar-Benitez, S. Ahlen, J. Alcaraz, et al.. Measurement of the Michel Parameters and the Average
-Neutrino Helicity from Decays at LEP. Physics Letters B, 1998, 438, pp.405-416. ⟨10.1016/S0920-5632(99)00452-1⟩. ⟨in2p3-00000025⟩ - M. Acciarri, O. Adriani, M. Aguilar-Benitez, S. Ahlen, J. Alcaraz, et al.. Determination of the Number of Light Neutrino Species from Single Photon Production at LEP. Physics Letters B, 1998, 431, pp.199-208. ⟨10.1016/S0370-2693(98)00519-X⟩. ⟨in2p3-00000026⟩
- M. Acciarri, O. Adriani, M. Aguilar Benitez, S. Ahlen, J. Alcaraz, et al.. Measurement of the
oscillation frequency. European Physical Journal C: Particles and Fields, 1998, 5, pp.195-203. ⟨10.1016/0370-2693(96)00768-X⟩. ⟨in2p3-00000083⟩ - M C. Abreu, B. Alessandro, A. Baldit, C. Barriere, M. Bedjidian, et al.. J/
and Drell-Yan production in pp and pd interactions at 450 GeV/c. Physics Letters B, 1998, 438, pp.35-40. ⟨10.1016/S0370-2693(98)01014-4⟩. ⟨in2p3-00005052⟩ - M. Chevallier, B. Cheynis, J.-Y. Grossiord, A. Guichard, D. Guinet, et al.. Proposal for the TC5/6 station of the ALICE dimuon arm. 1998, pp.10. ⟨in2p3-00011552⟩
- M. Acciarri, O. Adriani, M. Aguilar-Benitez, S. Ahlen, J. Alcaraz, et al.. Missing mass spectra in hadronic events from collisions at
=161-172 GeV and limits on invisible Higgs decays. Physics Letters B, 1998, 418, pp.389-398. ⟨10.1016/S0370-2693(97)01394-4⟩. ⟨in2p3-00000019⟩ - Xavier Artru, Robert Chehab, Katja Honkavaara, Alessandro Variola. Resolution power of optical transition radiation: Theoretical considerations. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1998, 145, pp.160-168. ⟨10.1016/S0168-583X(98)00402-9⟩. ⟨in2p3-00000007⟩
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