Hadron physics ALICE

  • Presentation
  • Activities
  • Members
  • Publications

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:

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 \rho, \omega and \phi 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 J/\psi and \Lambda 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 J/\psi and \Lambda mesons, namely the appearance of kinematic correlations between the J/\psi meson and light hadrons in high multiplicity proton-Pb collisions, and the observation of elliptical flow of the \Upsilon(1S) 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.

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    1804 documents

    • S. Beauceron, G. Cacciapaglia, A. Deandrea, J.D. Ruiz-Alvarez. Fully hadronic decays of a singly produced vector-like top partner at the LHC. Physical Review D, 2014, 90, pp.115008. ⟨10.1103/PhysRevD.90.115008⟩. ⟨in2p3-00935738⟩
    • Ammar Abdalgabar, Alan S. Cornell, A. Deandrea, Moritz Mcgarrie. Large A_{t} Without the Desert. Journal of High Energy Physics, 2014, 07(2014), pp.158. ⟨10.1007/JHEP07(2014)158⟩. ⟨in2p3-00995317⟩
    • A. Pastore, D. Davesne, J. Navarro. Nuclear matter response function with a central plus tensor Landau interaction. Journal of Physics G Nuclear Physics, 2014, 41, pp.055103. ⟨10.1088/0954-3899/41/5/055103⟩. ⟨in2p3-00920200⟩
    • K. Bennaceur. Density-independent interaction for nuclear structure calculations. FUSTIPEN Topical Meeting "Understanding nuclear structure and reactions microscopically including the continuum", 2014, Caen, France. ⟨in2p3-00973412⟩
    • H. Balasin, D.N. Blaschke, F. Gieres, M. Schweda. Wong's Equations and Charged Relativistic Particles in Non-Commutative Space. Symmetry, Integrability and Geometry : Methods and Applications, 2014, 10, pp.99. ⟨10.3842/SIGMA.2014.099⟩. ⟨in2p3-00999419⟩
    • G. Cacciapaglia, F. Sannino. Fundamental Composite (Goldstone) Higgs Dynamics. Journal of High Energy Physics, 2014, 04, pp.111. ⟨10.1007/JHEP04(2014)111⟩. ⟨in2p3-00941531⟩
    • G. Cacciapaglia. A passion for particles. Conference in honour of Riccardo Barbieri, Dec 2013, Pise, Italy. ⟨in2p3-00980210⟩
    • Sacha Davidson. The axion vs the WIMP. XIX IFT Xmas Workshop, Dec 2013, Madrid, Spain. ⟨in2p3-00976086⟩
    • Sacha Davidson. Baryogenesis and dark matter. New from the Dark, Dec 2013, Montpellier, France. ⟨in2p3-00976094⟩
    • C. KĂ©fĂ©lian. The muon veto system of the dark matter experiment EDELWEISS. JournĂ©es de Rencontres Jeunes Chercheurs 2013, Dec 2013, Barbaste, France. ⟨in2p3-00916946⟩

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