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:
- M. Chemarin, H. El Mamouni, J. Fay, G. Grenier, I. Laktineh, et al.. Search for production of neutral Higgs scalars in e
e
annihilations at LEP. International Conference on High Energy Physics 30 ICHEP 2000, Jul 2000, Osaka, Japan. ⟨in2p3-00010724⟩ - M. Chemarin, H. El Mamouni, J. Fay, G. Grenier, I. Laktineh, et al.. Search for scalar leptons in ee collisions at
= 192-202 GeV. International Conference on High Energy Physics 30 ICHEP 2000, Jul 2000, Osaka, Japan. ⟨in2p3-00010729⟩ - M.C. Abreu, B. Alessandro, C. Alexa, R. Arnaldi, M. Atayan, et al.. Results on open charm from NA50. International Conference on Strangeness in Quark Matter 5 Strangeness 2000, Jul 2000, Berkeley, United States. pp.677-684. ⟨in2p3-00007901⟩
- C. Quintans, M.C. Abreu, B. Alessandro, C. Alexa, R. Arnaldi, et al.. Production of the vector-meson in heavy ion collisions. International Conference on Strangeness in Quark Matter 5 Strangeness 2000, Jul 2000, Berkeley, United States. pp.405-412. ⟨in2p3-00009787⟩
- M. Abreu, B. Alessandro, C. Alexa, R. Arnaldi, M. Atayan, et al.. Enhancement of intermediate mass dimuons in nucleus-nucleus collisions at the CERN-SPS. Rencontres du Vietnam 4, Jul 2000, Hanoi, Vietnam. pp.509-518. ⟨in2p3-00011619⟩
- M. Abreu, B. Alessandro, C. Alexa, R. Arnaldi, M. Atayan, et al.. Evidence for deconfinement from the J/
suppression pattern in Pb-Pb collisions by the NA50 experiment. International Conference on Quark Confinement and the Hadron Spectrum 4, Jul 2000, Vienna, Austria. pp.357-360. ⟨in2p3-00010878⟩ - M. Monteno, M. Abreu, B. Alessandro, C. Alexa, R. Arnaldi, et al.. Results from the NA50 experiment on J/ suppression in PbPb collisions at the CERN SPS. International Workshop on Multiparticle Production ``New Frontiers in Soft Physics and Correlations on the Threshold of the Third Millenium 9, Jun 2000, Torino, Italy. pp.43-54. ⟨in2p3-00009840⟩
- P. Saturnini, M C. Abreu, B. Alessandro, C. Alexa, R. Arnaldi, et al.. Transverse flow in heavy ion interactions at the CERN SPS. International Workshop on Multiparticle Production 9 New Frontiers in Soft Physics and Correlations on the Threshold of the Third Millennium, Jun 2000, Torino, Italy. pp.55-61. ⟨in2p3-00009924⟩
- M. Abreu, B. Alessandro, C. Alexa, R. Arnaldi, M. Atayan, et al.. J/ suppression in ultrarelativistic heavy-ion collisions. International Conference on Nuclear Reaction Mechanisms 9, Jun 2000, Varenna, Italy. ⟨in2p3-00012153⟩
- M. Abreu, B. Alessandro, C. Alexa, R. Arnaldi, M. Atayan, et al.. Charmonium suppression in Pb-Pb collisions and quark-gluon deconfinement. Structure of the Nucleus at the Dawn of the Century, May 2000, Bologna, Italy. pp.91-97. ⟨in2p3-00010877⟩
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