Hadron physics

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 $\rho, \omega$ 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.

PERMANENTS:

NON-PERMANENTS:

- DOCTORANTS / DOCTORAL STUDENTS:

- CHERCHEURS NON-PERMANENTS / NON-PERMANENT RESEARCHERS:

BAILUNG Yoshini

663 documents

Shreyasi Acharya, Fernando Torales - Acosta, Dagmar Adamova, Jonatan Adolfsson, Madan Mohan Aggarwal, et al.. Transverse momentum spectra and nuclear modification factors of charged particles in Xe-Xe collisions at $\sqrt{s_{\rm NN}}$ = 5.44 TeV. Physics Letters B, 2019, 788, pp.166-179. ⟨10.1016/j.physletb.2018.10.052⟩. ⟨hal-01801872⟩
Shreyasi Acharya, Fernando Torales - Acosta, Dagmar Adamova, Souvik Priyam Adhya, Alexander Adler, et al.. Charged-particle pseudorapidity density at mid-rapidity in p-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 8.16 TeV. European Physical Journal C: Particles and Fields, 2019, 79 (4), pp.307. ⟨10.1140/epjc/s10052-019-6801-9⟩. ⟨hal-01960390⟩
Shreyasi Acharya, Fernando Torales - Acosta, Dagmar Adamova, Alexander Adler, Jonatan Adolfsson, et al.. Multiplicity dependence of light-flavor hadron production in pp collisions at $\sqrt{s}$ = 7 TeV. Physical Review C, 2019, 99 (2), pp.024906. ⟨10.1103/PhysRevC.99.024906⟩. ⟨hal-01862001⟩
A. Adare, S. Afanasiev, C. Aidala, N.N. Ajitanand, Y. Akiba, et al.. Measurement of two-particle correlations with respect to second- and third-order event planes in Au $+$ Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV. Physical Review C, 2019, 99 (5), pp.054903. ⟨10.1103/PhysRevC.99.054903⟩. ⟨hal-01802103⟩
C. Aidala, Y. Akiba, M. Alfred, V. Andrieux, K. Aoki, et al.. Creation of quark–gluon plasma droplets with three distinct geometries. Nature Physics, 2019, 15 (3), pp.214-220. ⟨10.1038/s41567-018-0360-0⟩. ⟨hal-01802043⟩
Aleksander Kusina, C. Hadjidakis, D. Kikola, J.P. Lansberg, L. Massacrier, et al.. Probing the high- $x$ content of the nuclei in the fixed-target mode at the LHC. 9th International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions, Oct 2018, Aix-Les-Bains, France. pp.110, ⟨10.22323/1.345.0110⟩. ⟨hal-02008900⟩
Cynthia Hadjidakis, S.J. Brodsky, G. Cavoto, C. da Silva, F. Donato, et al.. High-luminosity fixed-target experiments at the LHC. 9th International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions, Oct 2018, Aix-Les-Bains, France. pp.041, ⟨10.22323/1.345.0041⟩. ⟨hal-02059212⟩
Nodoka Yamanaka, C. Hadjidakis, D. Kikoła, J.P. Lansberg, L. Massacrier, et al.. Ultra-peripheral-collision studies in the fixed-target mode with the proton and lead LHC beams. 9th International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions, Oct 2018, Aix-Les-Bains, France. pp.184, ⟨10.22323/1.345.0184⟩. ⟨hal-02058535⟩
Antonio Uras. Heavy-flavour-production studies in a new energy and rapidity domain with AFTER@LHC. 9th International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions : Hard Probes 2018. (HP2018), Oct 2018, Aix-les-Bains, France. ⟨hal-02082243⟩
M.G. Echevarria, S.J. Brodsky, G. Cavoto, C. da Silva, F. Donato, et al.. Spin Physics with a fixed-target experiment at the LHC. 23rd International Symposium on Spin Physics, Sep 2018, Ferrara, Italy. pp.063, ⟨10.22323/1.346.0063⟩. ⟨hal-02080677⟩