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:
- J. Gascon. Prospects for Light WIMP searches with EDELWEISS. GDR Terascale @ Paris, Nov 2016, Paris, France. ⟨hal-02060105⟩
- G. Boudoul. Outer Tracker Simulation & Local Reconstruction. LPC Advanced Physics Workshop: Phase 2 Readiness for Physics with Full Simulation Event, Oct 2016, Batavia, United States. ⟨in2p3-02014281⟩
- K. Jourde, Dominique Gibert, J. Marteau, Jean de Bremond d'Ars, B. Carlus, et al.. The La Soufrière de Guadeloupe muon radiography acquisition setup. workshop From observations to processes at La Soufrière de Guadeloupe volcano : moving beyond the state-of-the-art in research and risk reduction, Oct 2016, Paris, France. ⟨hal-02087406⟩
- Dominique Gibert, J. Marteau, K. Jourde, Jean de Bremond d'Ars, B. Carlus, et al.. Functional imaging of La Soufrière volcano: New frontiers revealed by cosmic muons, electrical resistivity and gravity tomographies. workshop From observations to processes at La Soufrière de Guadeloupe volcano : moving beyond the state-of-the-art in research and risk reduction, Oct 2016, Paris, France. ⟨hal-02087392⟩
- Dominique Gibert, J. Marteau, K. Jourde, Jean de Bremond d'Ars, B. Carlus, et al.. Structural imaging and monitoring of the La Soufrière of Guadeloupe with muon radiography. workshop From observations to processes at La Soufrière de Guadeloupe volcano : moving beyond the state-of-the-art in research and risk reduction, Oct 2016, Paris, France. ⟨hal-02087399⟩
- Q. Arnaud, E. Armengaud, C. Augier, A. Benoît, L. Bergé, et al.. Signals induced by charge-trapping in EDELWEISS FID detectors: analytical modeling and applications. Journal of Instrumentation, 2016, 11 (10), pp.P10008. ⟨10.1088/1748-0221/11/10/P10008⟩. ⟨in2p3-01468429⟩
- N. Galy, N Toulhoat, N Moncoffre, N. Bérerd, Y Pipon, et al.. Effets de l’irradiation sur le comportement du
C et du
Cl implantés dans le graphite. IBAF 2016 - 6e Rencontre Ion Beam Analysis Francophone, Sep 2016, Annecy, France. ⟨in2p3-02094827⟩
- V. Sanglard. Recent results on Low Mass WIMP search with the EDELWEISS-III experiment. IDM2016, Jul 2016, Sheffield, United Kingdom. ⟨hal-02060088⟩
- Linda Feketeova. Velocity distributions of a molecule evaporated from mass-selected water nanodroplet. 7th International Meeting on Atomic and Molecular Physics and Chemistry, IMAMPC 2016, Jun 2016, Le Havre, France. ⟨in2p3-02072376⟩
- D. Contardo. Detector concepts for future colliders. Strategic Workshop on High Energy Particle Physics in Switzerland, Jun 2016, Lake Aegeri, Switzerland. ⟨hal-02063994⟩