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:
- A. Uras. Dimuon measurements in ALICE: The Muon Forward Tracker Upgrade Project. 5th International Conference on Hard and Electromagnetic Probes High-Energy Nuclear Collisions Hard Probes 2012, May 2012, Cagliari, Italy. ⟨in2p3-01019681⟩
- A. Uras. MFT simulations: Where we are. International Muon Workshop 2012, Apr 2012, Cape Town, South Africa. ⟨in2p3-01019708⟩
- B. Abelev, N. Arbor, G. Conesa Balbastre, J. Faivre, C. Furget, et al.. Measurement of Event Background Fluctuations for Charged Particle Jet Reconstruction in Pb-Pb collisions at
TeV. Journal of High Energy Physics, 2012, 1203 (2012), pp.053. ⟨10.1007/JHEP03(2012)053⟩. ⟨in2p3-00659804⟩ - B. Abelev, N. Arbor, G. Conesa Balbastre, J. Faivre, C. Furget, et al.. Pion, Kaon, and Proton Production in Central Pb--Pb Collisions at TeV. Physical Review Letters, 2012, 109, pp.252301. ⟨10.1103/PhysRevLett.109.252301⟩. ⟨in2p3-00723478⟩
- B. Abelev, J. Adam, D. Adamova, A. M. Adare, M. M. Aggarwal, et al.. Inclusive J/psi production in pp collisions at sqrt(s) = 2.76 TeV. Physics Letters B, 2012, 718, pp.295-306. ⟨10.1016/j.physletb.2012.10.078⟩. ⟨in2p3-00680363⟩
- B. Abelev, N. Arbor, G. Conesa Balbastre, J. Faivre, C. Furget, et al.. Neutral pion and
meson production in proton-proton collisions at 
TeV and 
TeV. Physics Letters B, 2012, 717, pp.162-172. ⟨10.1016/j.physletb.2012.09.015⟩. ⟨in2p3-00703615⟩ - B. Abelev, Laurent Aphecetche, A. Baldisseri, Guillaume Batigne, I. Belikov, et al.. Suppression of high transverse momentum D mesons in central Pb--Pb collisions at
TeV. Journal of High Energy Physics, 2012, 9, pp.112. ⟨10.1007/JHEP09(2012)112⟩. ⟨in2p3-00678268⟩ - K. Aamodt, Sang Un Ahn, Laurent Aphecetche, N. Arbor, Y.W. Baek, et al.. Harmonic decomposition of two-particle angular correlations in Pb--Pb collisions at
TeV. Physics Letters B, 2012, 708, pp.249-264. ⟨10.1016/j.physletb.2012.01.060⟩. ⟨in2p3-00622891⟩ - B. Abelev, Laurent Aphecetche, A. Baldisseri, Guillaume Batigne, I. Belikov, et al.. Measurement of electrons from semileptonic heavy-flavour hadron decays in pp collisions at \sqrt{s} = 7 TeV. Physical Review D, 2012, 86, pp.112007. ⟨10.1103/PhysRevD.86.112007⟩. ⟨in2p3-00701429⟩
- B. Abelev, N. Arbor, G. Conesa Balbastre, J. Faivre, C. Furget, et al.. Transverse sphericity of primary charged particles in minimum bias proton-proton collisions at sqrt(s)=0.9, 2.76 and 7 TeV. European Physical Journal C: Particles and Fields, 2012, 72, pp.2124. ⟨10.1140/epjc/s10052-012-2124-9⟩. ⟨in2p3-00699404⟩
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