The pseudorapidity dependence of charged particle production provides information on the partonic structure of the colliding hadrons. It is especially interesting at LHC energies, as this observable is sensitive to the non-linear QCD evolution of the initial state. For the Run 3 of LHC, ALICE has upgraded its detectors, increasing its pseudorapidity coverage and tracking of charged particles...
The production of charm quarks and charmonium states in fixed-target collisions provides a powerful probe of QCD in cold and hot nuclear matter. The LHCb experiment has pioneered a novel fixed-target program, now enhanced for Run 3 with the SMOG2 system, which features improved gas confinement and the capability to inject non-noble gases. This upgrade significantly increases fixed-target...
Modifications of quarkonia production in hadronic collisions provide an important experimental observable to probe the heavy quark interaction with the nuclear medium. The excited ψ(2S) state, with a relatively low binding energy, is especially sensitive to these effects. Different phenomena can be probed by studying the excited-to-ground state production ratio in different collision systems...
The measurement of dielectron production is a fundamental piece of the puzzle in the understanding of the hot and dense matter produced in ultra-relativistic heavy-ion collisions. The dielectron spectrum provides information that penetrates the veil of final-state hadronic interactions and provides direct access to the early phases of the collision. However, the interpretation of the measured...
Correlation femtoscopy is a well-known tool used in nucleus-nucleus collision experiments for studying space-time properties of the particle-emitting source via momentum correlations based on the laws of quantum statistics, Coulomb and strong interactions. In this talk, the most recent results of femtoscopic analysis of identical proton pairs measured by ALICE in various collision systems (pp...
The study of the Quark-Gluon Plasma (QGP), a deconfined state of nuclear matter, remains a central focus of high-energy heavy-ion collision experiments. Light-flavor hadrons act as essential probes of the QGP, offering insights into its bulk properties. In particular, the pseudorapidity density of charged particles, which reflects the energy density achieved in such collisions, serves as a key...
We discuss factorization of jet cross sections in heavy-ion collisions. First, using Glauber modelling of heavy nuclei, a factorized formula for jet cross sections is derived, which involves defining a virtuality-dependent jet functions in QCD medium. Then, we generalize the BDMPS-Z formalism to evaluate the jet function initiated by a parton with virtuality $m_I^2$. At the end, we disucss the...
The production of top quarks in heavy ion collisions serves as a novel tool for investigating nuclear parton distribution functions at high Bjorken-x. Although being a quark, the top has a short lifetime, decaying predominantly to a W boson and b quark pair, before hadronizing. Leptonic final states from the subsequent W boson decay are thus effectively electroweak probes of the medium they...
Accurate modeling and understanding of quarkonium production in AA collisions requires a formalism that preserves the quantum properties of a microscopic $Q\bar{Q}$ system while treating the interaction of such pairs with the QGP. The open quantum system approach has recently emerged as one of the most fruitful schemes to meet such requirements. However, the quantum master equations obtained...
We studied the diffractive photoproduction of $J/\psi$ mesons at the highest available energies.The data from ultraperipheral collisions (UPCs) are well described at high energies/small-$x$ after including additional shadowing from the $c \bar c g$ Fock state.
We confront our results on diffractive photoproduction of $J/\psi$ mesons with the putative gluon shadowing ratio defined as $R_g=...
One of the main challenges in nuclear physics is studying the structure of the atomic nucleus. Recently, it has been shown that relativistic nuclear collisions at RHIC and the LHC can complement low-energy experiments. Relativistic nuclear collisions provide a snapshot of the nuclear distribution at the time of collisions, offering a precise probe of the nuclear structure.
In this talk, I...
Heavy quarks (charm and beauty) are useful probes for investigating the properties of the quark-gluon plasma (QGP) generated in ultra-relativistic heavy-ion collisions. Their participation in the collective motion of the medium can be assessed by measuring the prompt and non-prompt charm-hadron elliptic-flow coefficient $v_2$, originating from the initial-state spatial asymmetry in non-central...
The energy-loss of high-momentum jets, as they traverse the hot and deconfined quark-gluon plasma (QGP) produced in heavy-ion collisions, is one of the key observables used to characterize medium properties. In particular, the ability of the medium to dissipate the lost energy of the jet provides vital information on the transport properties of the QGP. The dissipative power of the medium can...
Particle production in heavy-ion collisions exhibits collective behavior known as collective flow, arising from the pressure-driven expansion of the quark-gluon plasma (QGP) formed in these collisions. Anisotropies in the azimuthal distribution of final-state particles can generate local vorticities in the QGP along the beam axis. Through spin-orbit coupling, these vorticities are expected to...
Measurements of top-quark pairs in heavy-ion collisions are expected to provide novel probes of nuclear parton distribution functions as well as to bring unique information about the time evolution of strongly interacting matter. We report the observation of top-quark pair production in proton-lead collisions at the centre-of-mass energy of 8.16 TeV in the ATLAS experiment at the LHC....
Ultra-peripheral collisions enable a variety of two-photon and photonuclear interactions to be studied. Earlier analyses have mostly focused on exclusive photonuclear vector meson production and on two-photon interactions. This presentation will be on photonuclear interactions where the target nucleus breaks up. The cross sections for these interactions are huge in Pb-Pb collisions at the LHC....
The study of jet substructure has given rise to a new era of precision quantum-chromodynamics (QCD) measurements related to the evolution of the parton shower. In order to better understand the role of the quark mass, the decay kinematics of the heavy flavor hadrons need to be isolated from the QCD branchings. This talk presents new CMS results on the groomed jet radius Rg and momentum balance...
Prompt photon production in pA collisions has long been suggested as a sensitive probe of the nuclear gluon density. In this study, we present recent results on another cold nuclear matter effect: fully coherent radiation induced by parton multiple scattering, which may affect the nuclear dependence of prompt photon production. Medium-induced radiation effects, implemented in leading-order...
Relativistic heavy-ion collisions create a hot, dense state of QCD matter called Quark–Gluon Plasma (QGP). In ultra-central collisions, the QGP volume saturates and remains constant; instead, entropy fluctuations cause temperature variations in the system. This property can be probed by measuring the correlation between the average transverse momentum (⟨$p_{\rm T}$⟩) and the multiplicity of...
Hypernuclei are bound states of nucleons and hyperons. The measurement of the production of hypernuclei with mass number A=3 and 4 in heavy-ion collisions is a powerful tool to investigate the hyper-nucleosynthesis mechanism. In the coalescence model, the production yields are sensitive to the interplay between the spatial extension of the nucleus wavefunction and the baryon-emitting source...
Quarkonium production has long been identified as one of the golden probes to study the quark-gluon plasma (QGP). Among many observables, the measurement of azimuthal anisotropies in quarkonium production has a special role to shed light on the collective behavior of particles in a strongly interacting medium. In particular, the magnitude of the $\rm{J}/\psi$ elliptic flow measured at the LHC...
Measurements of heavy baryon production in pp, pA and AA collisions from RHIC to top LHC energies have recently attracted more and more attention, currently representing a challenge for the heavy-quark hadronization theoretical understanding. In such experiments there have been many indications of the formation of a deconfined phase of quarks and gluons called the quark-gluon-plasma (QGP)....
One of the most effective techniques for investigating the mechanism of baryon production is the study of angular correlations between two particles. Angular correlations represent a convolution of various physical processes, such as mini-jets, Bose-Einstein quantum statistics, conservation of momentum, resonances, and other phenomena that contribute to the unique behavior observed for...
Recent PP collisions at the highest available LHC energies (at 13 TeV CM energies) are performed with such a high luminosity, when the detected multiplicity dependence can be observed by high precision and its microscopical origin can be studied and discussed. Indeed, the measured hadron transverse momentum spectra differ at lower and higher final state multiplicities, which offers the...
The enhanced production of strange hadrons in heavy-ion collisions relative to that in pp collisions is historically considered one of the signatures of the formation of the quark-gluon plasma. At the LHC, the ALICE experiment observed that the yield ratios of strange to non-strange hadrons increase with the charged-particle multiplicity at midrapidity, evolving smoothly across all systems...
We present a complete one-loop study of exclusive vector quarkonium photoproduction off protons in Collinear Factorisation (CF), including GPD evolution. The notoriously large scale instability of the cross section at high energies at next-to-leading order (NLO) is confirmed and resolved by resumming leading-logarithmic QCD corrections via High-Energy Factorisation (HEF) in the...
In ultra-relativistic heavy-ion collisions, high rates of $\gamma\gamma$ processes occur through the interaction of the large electromagnetic fields of the heavy nuclei. For large impact parameters between the nuclei, i.e. interaction distances larger than the nuclei's radii, the di-photon interaction can be the only one taking place, leading to very clean signatures in the detector. One of...
Jets are essential hard probes for investigating the early-time dynamics and structure of the quark-gluon plasma in heavy-ion collisions. We develop an analytical framework for radiative energy loss in evolving media using resummation techniques, capturing both rare and multiple scattering regimes. Our results highlight the sensitivity of jet observables to early-time medium properties,...
