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:
- Shreyasi Acharya, Dagmar Adamova, Gianluca Aglieri Rinella, Michelangelo Agnello, Neelima Agrawal, et al.. Common femtoscopic hadron-emission source in pp collisions at the LHC. European Physical Journal C: Particles and Fields, 2025, 85 (2), pp.198. ⟨10.1140/epjc/s10052-025-13793-y⟩. ⟨hal-04323194⟩
- Shreyasi Acharya, Apar Agarwal, Gianluca Aglieri Rinella, Luca Aglietta, Michelangelo Agnello, et al.. Medium-induced modification of groomed and ungroomed jet mass and angularities in Pb-Pb collisions at
TeV. Phys.Lett.B, 2025, 864, pp.139409. ⟨10.1016/j.physletb.2025.139409⟩. ⟨hal-04791718⟩ - Shreyasi Acharya, Dagmar Adamova, Apar Agarwal, Gianluca Aglieri Rinella, Luca Aglietta, et al.. Measurement of the inclusive isolated-photon production cross section in pp collisions at
= 13 TeV. Eur.Phys.J.C, 2025, 85 (1), pp.98. ⟨10.1140/epjc/s10052-024-13506-x⟩. ⟨hal-04642107⟩ - Shreyasi Acharya, Dagmar Adamova, Alexander Adler, Gianluca Aglieri Rinella, Michelangelo Agnello, et al.. Multiplicity dependence of
production at forward rapidity in pp collisions at = 13 TeV. Nucl.Phys.B, 2025, 1011, pp.116786. ⟨10.1016/j.nuclphysb.2024.116786⟩. ⟨hal-04692644⟩ - Shreyasi Acharya, Dagmar Adamova, Alexander Adler, Gianluca Aglieri Rinella, Michelangelo Agnello, et al.. First polarisation measurement of coherently photoproduced J/
in ultra-peripheral Pb
Pb collisions at 
= 5.02 TeV. Phys.Lett.B, 2025, 865, pp.139466. ⟨10.1016/j.physletb.2025.139466⟩. ⟨hal-04757639⟩ - Shreyasi Acharya, Dagmar Adamova, Apar Agarwal, Gianluca Aglieri Rinella, Luca Aglietta, et al.. Probing strangeness hadronization with event-by-event production of multistrange hadrons. Physical Review Letters, 2025, 134 (2), pp.022303. ⟨10.1103/PhysRevLett.134.022303⟩. ⟨hal-04600667⟩
- N.J Abdulameer, U Acharya, C Aidala, N.N Ajitanand, Y Akiba, et al.. Measurement of inclusive jet cross section and substructure in
collisions at 
GeV. Phys.Rev.D, 2025, 111 (11), pp.112008. ⟨10.1103/hpm9-qfp6⟩. ⟨hal-04685720⟩ - Shreyasi Acharya, Dagmar Adamova, Apar Agarwal, Gianluca Aglieri Rinella, Luca Aglietta, et al.. Rapidity dependence of antideuteron coalescence in pp collisions at = 13 TeV with ALICE. Phys.Lett.B, 2025, 860, pp.139191. ⟨10.1016/j.physletb.2024.139191⟩. ⟨hal-04660001⟩
- Shreyasi Acharya, Apar Agarwal, Gianluca Aglieri Rinella, Luca Aglietta, Michelangelo Agnello, et al.. Measurement of f
(1285) production in pp collisions at 
= 13 TeV. Phys.Lett.B, 2025, 866, pp.139562. ⟨10.1016/j.physletb.2025.139562⟩. ⟨hal-04710159⟩ - Shreyasi Acharya, Apar Agarwal, Gianluca Aglieri Rinella, Luca Aglietta, Michelangelo Agnello, et al.. First observation of strange baryon enhancement with effective energy in pp collisions at the LHC. JHEP, 2025, 03, pp.029. ⟨10.1007/JHEP03(2025)029⟩. ⟨hal-04710161⟩
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