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:
- Michael Urban, S. Chiacchiera, D. Davesne, T. Lepers. Damping of collective modes in ultracold trapped Fermi gases with inmedium cross section. Many-body corelations from dilute to dense nuclear systems (MBC 2011), Feb 2011, Paris, France. ⟨in2p3-00664910⟩
- N. Redon. Missing Links in the Series of the Superdeformed Lead Nuclei along Isospin Content. SPIRAL2 Week, Jan 2011, Caen, France. ⟨in2p3-00765355⟩
- C. Gaillard, N. Toulhoat, N. Moncoffre, D. Roudil, M. PĂ©rez, et al.. Comportement thermique du cĂ©sium dans un pyrocarbone. JournĂ©es PlĂ©nières du GnR MATINEX, Jan 2011, Limoges, France. ⟨in2p3-01018546⟩
- S. Gavarini, M. Gherrab, N. Millard-Pinard, C. Gaillard, C. Peaucelle, et al.. Synthèse, comportement thermique et sous irradiation de TiN et TiC synthĂ©tisĂ©s par HP et SPS. JournĂ©es PlĂ©nières du GnR MATINEX, Jan 2011, Limoges, France. ⟨in2p3-01018544⟩
- O. StĂ©zowski. Status Report from the GEANT4 simulation WG. Paris Week, Jan 2011, Strasbourg, France. ⟨in2p3-00765325⟩
- X. Artru. String fragmentation model with quark spin. 3rd International Conference on Quantum Electrodynamics and Statistical Physics (AEDSP2011), 2011, Kharkov, Ukraine. pp.173-178. ⟨in2p3-00749644⟩
- I. Billard, A. Ouadi, C. Gaillard. Liquid-liquid extraction of actinides, lanthanides, and fission products by use of ionic liquids: from discovery to understanding. Analytical and Bioanalytical Chemistry, 2011, 400, pp.1555-1566. ⟨10.1007/s00216-010-4478-x⟩. ⟨in2p3-00734055⟩
- S. Chatrchyan, D. Sillou, M. Besancon, S. Choudhury, M. Dejardin, et al.. Measurement of energy flow at large pseudorapidities in pp collisions at
= 0.9 and 7 TeV. Journal of High Energy Physics, 2011, 11, pp.148. ⟨10.1007/JHEP11(2011)148⟩. ⟨in2p3-00628688⟩ - S. Chatrchyan, D. Sillou, M. Besancon, S. Choudhury, M. Dejardin, et al.. Measurement of the t t-bar Production Cross Section in pp Collisions at 7 TeV in Lepton + Jets Events Using b-quark Jet Identification. Physical Review D, 2011, 84, pp.092004. ⟨10.1103/PhysRevD.84.092004⟩. ⟨in2p3-00624257⟩
- S. Chatrchyan, D. Sillou, M. Besancon, S. Choudhury, M. Dejardin, et al.. Search for Supersymmetry at the LHC in Events with Jets and Missing Transverse Energy. Physical Review Letters, 2011, 107, pp.221804. ⟨10.1103/PhysRevLett.107.221804⟩. ⟨in2p3-00622884⟩
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