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:
- X. Artru. Petit tour autour du spin. Journees d'Etudes Experimentateurs Theoriciens 3, Nov 1999, Aubiere, France. pp.290-307. ⟨in2p3-00009681⟩
- M.C. Abreu, B. Allessandro, C. Alexa, R. Arnaldi, J. Astruc, et al.. Charmonium production in Pb-Pb collisions at 158 A GeV. Indian Summer School on the Relativistic Heavy-Ion Physics 12, Aug 1999, Prague, Czech Republic. pp.114-119. ⟨in2p3-00019692⟩
- D. Idzik, M.C. Abreu, B. Alessandro, C. Alexa, R. Arnaldi, et al.. Summary of J/
suppression data and preliminary results on multiplciity distributions in Pb-Pb collisions from the NA50 experiment. International Symposium on Multiparticle Dynamics 29, Aug 1999, Providence,Rhod Island, United States. ⟨in2p3-00012123⟩ - A. de Falco, M.C. Abreu, B. Alessandro, C. Alexa, R. Arnaldi, et al.. Study of J/
suppression in Pb-Pb collisions at the CERN SPS. International Europhysics Conference on High Energy Physics HEP-EPS 99, Jul 1999, Tampere, Finland. pp.959-961. ⟨in2p3-00007902⟩ - J. Marteau, J. Delorme, M. Ericson. Effets nucleaires dans les interactions de neutrinos atmospheriques avec des noyaux. NUFACT'99, Jul 1999, Lyon, France. pp.7. ⟨in2p3-00003813⟩
- J. Marteau, J. Delorme, M. Ericson. Nuclear effects in neutrino-nucleus interactions. ICFA/ECFA Workshop on Neutrino Factories based on Muon Storage Rings - NUFACT'99, Jul 1999, Lyon, France. pp.8. ⟨in2p3-00005629⟩
- J.-P. Walder, H. El Mamouni, P. Pangaud. High speed wide dynamic range analog signal processing for avalanche photodiode. International Conference on New Developments in Photodetection 2, Jun 1999, Beaune, France. pp.384-389. ⟨in2p3-00007775⟩
- M. Ericson, G. Chanfray, J. Delorme, M. Rosa-Clot. Manifestations of chiral symmetry restoration in photon reactions. International Conference on Particles and Nuclei 15 PANIC'99, Jun 1999, Uppsala, Sweden. pp.369c-372c. ⟨in2p3-00007761⟩
- M.P. Comets, M.C. Abreu, B. Alessandro, C. Alexa, R. Arnaldi, et al.. Strangeness measurements in NA50 experiment with Pb projectiles. International Conference on Particles and Nuclei. 15 PANIC '99, Jun 1999, Uppsala, Sweden. pp.721c-724c. ⟨in2p3-00005337⟩
- N. de Marco, M.C. Abreu, B. Alessandro, C. Alexa, R. Arnaldi, et al.. Charmonium production in Pb-Pb collisions. International Conference on Particles and Nuclei. 15 PANIC '99, Jun 1999, Uppsala, Sweden. pp.765c-768c. ⟨in2p3-00005338⟩
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