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:
- S. Chatrchyan, D. Sillou, M. Besancon, S. Choudhury, M. Dejardin, et al.. Measurement of the Rapidity and Transverse Momentum Distributions of Z Bosons in pp Collisions at sqrt(s)=7 TeV. Physical Review D, 2012, 85, pp.032002. ⟨10.1103/PhysRevD.85.032002⟩. ⟨in2p3-00635304⟩
- S. Chatrchyan, M. Besancon, S. Choudhury, M. Dejardin, D. Denegri, et al.. Search for charge-asymmetric production of W' bosons in top pair + jet events from pp collisions at sqrt(s) = 7 TeV. Physics Letters B, 2012, 717, pp.351-370. ⟨10.1016/j.physletb.2012.09.048⟩. ⟨in2p3-00709564⟩
- Ze-Kun Guo, S. Narison, J.-M. Richard, Qiang Zhao. Isospin violating decay of
. Physical Review D, 2012, 85, pp.114007. ⟨10.1103/PhysRevD.85.114007⟩. ⟨in2p3-00686368⟩ - S. Chatrchyan, D. Sillou, M. Besancon, S. Choudhury, M. Dejardin, et al.. Forward Energy Flow, Central Charged-Particle Multiplicities, and Pseudorapidity Gaps in W and Z Boson Events from pp Collisions at 7 TeV. European Physical Journal C: Particles and Fields, 2012, 72, pp.1839. ⟨10.1140/epjc/s10052-011-1839-3⟩. ⟨in2p3-00628687⟩
- B. Abelev, N. Arbor, G. Conesa Balbastre, J. Faivre, C. Furget, et al.. Heavy flavour decay muon production at forward rapidity in proton--proton collisions at \sqrt(s) = 7 TeV. Physics Letters B, 2012, 708, pp.265-275. ⟨10.1016/j.physletb.2012.01.063⟩. ⟨in2p3-00661263⟩
- B. Abelev, N. Arbor, G. Conesa Balbastre, J. Faivre, C. Furget, et al.. J/psi polarization in pp collisions at sqrt(s)=7 TeV. Physical Review Letters, 2012, 108, pp.082001. ⟨10.1103/PhysRevLett.108.082001⟩. ⟨in2p3-00639319⟩
- N. Toulhoat, N. Moncoffre, Y. Pipon, N. BĂ©rerd, G. Silbermann, et al.. Synergistic or decoupled effects of temperature and irradiation on 14C and 36Cl behavior in irradiated graphite studied through ion implantation or irradiation of virgin nuclear graphite. Irradiation damage and formation in Nuclear Graphite Joint meeting in conjunction with the FP7 Carbowaste program, 2012, Manchester, United Kingdom. ⟨in2p3-01018590⟩
- G. Cacciapaglia. LHC missing-transverse-energy constraints on models with universal extra dimensions. GDR Terascale meeting GDR Terascale@Montpellier, 2012, Montpellier, France. ⟨in2p3-00982036⟩
- B. Abelev, Laurent Aphecetche, A. Baldisseri, Guillaume Batigne, I. Belikov, et al.. Measurement of prompt and non-prompt J/psi production cross sections at mid-rapidity in pp collisions at sqrt(s) = 7 TeV. Journal of High Energy Physics, 2012, 2012, pp.065. ⟨10.1007/JHEP11(2012)065⟩. ⟨in2p3-00702009⟩
- S. Chatrchyan, D. Sillou, M. Besancon, S. Choudhury, M. Dejardin, et al.. Measurement of isolated photon production in pp and PbPb collisions at sqrt(sNN) = 2.76 TeV. Physics Letters B, 2012, 710, pp.256-277. ⟨10.1016/j.physletb.2012.02.077⟩. ⟨in2p3-00660551⟩
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