arXiv subjects

for the ALICE Collaboration

Publications and source records attributed to for the ALICE Collaboration.

6 recordsLinked to original sources

arXiv2026

Probing the initial geometry and the onset of collectivity with anisotropic flow in light-ion collisions with ALICE at the LHC

Collective behavior, traditionally associated with heavy-ion collisions, has been observed in small collision systems at the LHC. The recent oxygen-oxygen and neon-neon collisions allow to bridge the gap between small and large collision systems and to study the collectivity in well-constrained initial states. Measurements of azimuthal anisotropies are sensitive to the initial-state geometry and enable detailed investigations of the nuclear structure of $^{16}$O and $^{20}$Ne, highlighting the interplay between nuclear structure and collective dynamics in ultrarelativistic collisions. This contribution presents recent anisotropic flow measurements performed by the ALICE Collaboration in OO and Ne-Ne collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.36 TeV using two- and multiparticle correlation methods. The results are compared to hydrodynamic calculations incorporating the possible nuclear structures of these light nuclei, providing stringent constraints on the modeling of the initial state. In addition, prospects for measuring long-range correlations with the forward ALICE detectors are discussed, with the aim of studying the longitudinal dependence of anisotropic flow and thereby constraining the longitudinal structure of the initial state.

nucl-ex↗

arXiv2026

Multimuon Events from Cosmic Rays with the ALICE Detector

ALICE experiment at the CERN's Large Hadron Collider, carried out a cosmic data-taking campaign in the period 2015-2018 (LHC Run 2), for a total of 62.5 days of real observation time. In this contribution, the analysis of these data is limited to multimuon events, i.e. events with more than four detected muons. In particular, the muon multiplicity distribution (MMD) is studied in the low-intermediate multiplicity range ($4 < N_μ < 50$), while for multiplicities $N_μ > 100$, dominated by large statistical fluctuations of the data, the rate of the high muon multiplicity events (HMM) is measured. The results are compared with Monte Carlo simulations using three of the main hadronic interaction models describing the air shower development in the atmosphere: QGSJET-II-04, EPOS-LHC, and SIBYLL 2.3d, and assuming two extreme compositions of primary cosmic rays, pure proton and pure iron, representing respectively the lightest and the heaviest composition. Although the models have difficulty precisely describing the trend of primary p and Fe as a function of cosmic ray primary energy, QGSJET-II-04 is the only model that reproduces reasonably well the MMD and the rate of HMM events assuming a heavy composition for the entire energy range studied.

astro-ph.HE↗

arXiv2026

Anisotropic flow measurements in OO and Ne-Ne collisions with ALICE

The LHC results have demonstrated that small collision systems can exhibit collective behavior reminiscent of that~observed in heavy-ion collisions, opening a new frontier for exploring the connection between nuclear structure and collective dynamics at ultra-relativistic energies. However, the interpretation of collectivity in small collision systems is limited by understanding the proton subnucleonic structure. The ${}^{16}$O and ${}^{20}$Ne collisions delivered by the LHC offer an opportunity to study the influence of nuclear geometry on anisotropic flow in systems where the nuclear structure is well-constrained. In this proceeding, measurements of the anisotropic flow of charged particles, $v_n$, in OO and Ne-Ne collisions involving up to eight-particle correlations are presented, using the multi-particle cumulant method. Furthermore, the first reconstruction of the probability distribution function of elliptic flow $P(v_2)$, and the first measurement of the ratio $v_3\{4\}/v_3\{2\}$ in light-ion collision systems are reported. These measurements provide deeper insight into the role of nuclear geometry-driven flow in light-ion collisions.

nucl-ex↗

arXiv2026

Heavy-flavour production and correlations in pp collisions: precision tests of pQCD and hadronisation with ALICE

Heavy quarks (charm and beauty) are predominantly produced in hard partonic scatterings, making their cross sections in proton--proton (pp) collisions calculable in perturbative quantum chromodynamics (pQCD) and thus providing stringent tests of pQCD. Furthermore, the associated production of two charm hadrons in a single collision offers a sensitive probe of multiparton interaction dynamics, distinguishing between single parton scattering (SPS) and double parton scattering (DPS) processes. In this contribution, preliminary measurements of prompt D-meson production are reported, together with the final results of the $\rm B^{0}$-meson production cross section down to $p_{\rm T}$ = 1 GeV/$c$ at midrapidity. The rapidity dependence of B-meson production is investigated by computing the ratio with respect to LHCb measurements at forward rapidity. The associated production of $\rm D^{0}$--$\mathrm{J}/ψ$ pairs in pp collisions at $\sqrt{s} = 13.6$ TeV is presented as well, where $\rm D^{0}$ mesons are reconstructed at midrapidity, while $\mathrm{J}/ψ$ candidates are measured at forward rapidity. These measurements are compared with pQCD calculations and phenomenological models, providing crucial constraints on heavy-quark production, hadronisation, and multiparton interaction dynamics.

hep-ex↗

arXiv2022

Upgrade of the ALICE experiment beyond LHC Run 3

The ALICE Collaboration completed the upgrade of the detector and is now commissioning for the beginning of the data taking during LHC Run 3. In parallel, R&D activities and simulation studies are being performed to define the future of the experiment beyond LHC Run 3. Two detector upgrades are foreseen for the next long shutdown (LS3). The first is the replacement of the three layers of the inner tracking system closest to the beam with a novel vertex detector consisting of curved wafer-scale ultra-thin silicon sensors arranged in perfectly cylindrical layers to improve impact parameter resolution and significantly extend the physics capability for the study of the heavy-flavor production and the low-mass dielectrons. The second upgrade for the LS3 is the addition of a Forward Calorimeter detector at large rapidity consisting of a Si-W electromagnetic calorimeter with pad and pixel readout, that will equip the experiment with unique capabilities to measure small-x gluon distributions via prompt photon production. A proposal of a next-generation heavy-ion experiment for LHC Run 5 is also in preparation and will be discussed. The aim is to perform novel measurements of the electromagnetic and hadronic probes of the QGP, such as the production of multiply-charmed baryons, which have so far been inaccessible, both because of detector performance and luminosity. The concept of the new apparatus foresees an extensive usage of thin silicon sensors for tracking and a modern particle identification system, combining a silicon-based time of flight detector, a RICH detector, an electromagnetic calorimeter and a muon system.

hep-ex↗

arXiv2020

Investigating Hard Splittings via Jet Substructure in pp and Pb-Pb Collisions at $\sqrt{s_{\mathrm{NN}}} = 5.02$ TeV with ALICE

Jets lose energy as they propagate through the Quark-Gluon Plasma, modifying their parton shower. Jet substructure, which provides access to the evolution of jet splittings, is expected to be sensitive to interactions between the medium and the jet, providing the opportunity to further constrain both jet and medium properties. By utilizing grooming techniques, we can focus on the most pertinent hard splittings. Of particular interest is the search for large transverse momentum kicks which may indicate the presence of point-like scatters within the Quark-Gluon Plasma. We explore the jet substructure of inclusive jets in pp and Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}} = 5.02$ TeV, utilizing Soft Drop and other grooming methods, as well as the Lund Plane, in order to access the hardest jet splitting, with a particular focus on the hardest $k_{\mathrm{T}}$ splitting.

nucl-ex↗