The ALICE experiment has undergone major upgrades during the LHC long shutdown 2, to make both detectors and computing infrastructure cope with the increased luminosity of LHC in Run 3 (2022-25).
The Inner Tracking System and the Time Projection Chamber have been significantly upgraded and new Muon Forward Tracker and Fast Interaction Trigger detectors have been installed. Also, the readout...
The quark-gluon plasma created in high-energy heavy-ion collisions has been conjectured to exhibit a spontaneous electric-charge separation in the direction of a strong magnetic field through the chiral magnetic effect (CME). The experimental confirmation of the CME in heavy-ion collisions will uncover fundamental aspects of strong interaction physics such as the QCD chiral symmetry...
The measurement of azimuthal correlations between two particles is a powerful tool to investigate the properties of strongly-interacting nuclear matter created in ultra-relativistic heavy-ion collisions. In particular, studying the near-and away-side hadron yields associated with trigger particles can provide important information to understand both the jet-medium interaction and hadron...
Measurements of reconstructed jets and jet substructure offer opportunities to study fragmentation in a nuclear environment. However, at RHIC this promise is complicated by the low jet energies and lack of hadronic calorimetry in the current experiments. In this poster, we report new results with reconstructed jets, including substructure measurements applying jet grooming techniques, in p+p...
To understand properties of strongly interacting matter especially in a heavy flavor sector or thermal radiation of plasma the ALICE experiment has significantly upgraded its detectors. In order to improve the pointing resolution and readout rates, a completely new silicon-pixel Inner Tracking System (ITS) was installed and extended to cover the acceptance of the forward muon detectors with a...
ALICE (A Large Ion Collider Experiment), one of the CERN Large Hadron Collider (LHC) experiments, was originally designed to study the physics of heavy-ion collisions. It was designed to detect, track, and identify particles in high-energy collisions up to the largest particle multiplicities. In its first decade of activity, ALICE Collaboration studied the hot and dense medium formed in...
Polarization of Lambda hyperons, produced in relativistic heavy-ion collisions, has been discovered in 2017 by STAR experiment in the Beam-Energy Scan program at RHIC. The trends in the global Lambda polarization are in good agreement with hydrodynamic models. However, the transverse momentum dependence of polarization components in the out-of-plane direction and beam direction does not agree...
In this talk we will focus on the most recent highlights from the ongoing data analysis of the PHENIX experiment.
The Solenoidal Tracker at RHIC (STAR) detector has excellent tracking and particle identification capabilities, as well as an electromagnetic calorimeter of fine granularity at mid-rapidity, which makes STAR a unique experiment to study the emergent properties of Quantum Chromodynamics (QCD) and Quantum electrodynamics (QED). The main physics goal of the heavy-ion collisions at RHIC top energy...
We calculate the total and partial shear viscosity of hadrons produced in central gold-gold collisions at intermediate energies [1,2]. For calculations of the collisions the transport model UrQMD is employed. The shear viscosity is obtained within the framework of Green-Kubo formalism. The hadron resonance gas (HRG) model is used to determine temperature and chemical potentials of baryon...
The upcoming sPHENIX experiment is the next generation of large acceptance detector at RHIC, whose scientific goals center on probing the strongly interacting Quark-Gluon Plasma (QGP) with precision measurements of jets, heavy flavor, and upsilon production. The sPHENIX experiment is currently under construction and scheduled for first data in early 2023. Built around the excellent BaBar...
Within the FAIR Phase-0 program the algorithms of the FLES (First-Level Event Selection) package developed for the CBM experiment (FAIR/GSI, Germany) are adapted for online and offline processing in the STAR experiment (BNL, USA).
Long-lived charged particles are reconstructed in the Time Projection Chamber using the CA track finder algorithm based on the Cellular Automaton. The search for...
In ultra-relativistic heavy-ion collisions, a dense and hot QCD medium, called the Quark-Gluon Plasma (QGP) and composed of de-confined quarks and gluons, is created. Heavy quarks (charm and beauty) are produced dominantly in hard partonic scatterings in the early stage of the collisions and experience the whole medium evolution. Therefore, they are ideal probes to investigate the QGP...
Heavy flavor and quarkonia production is a powerful tool to study the properties of the Quark Gluon Plasma (QGP). Heavy quarks lose their energies via final state interactions in the QGP. The magnitude of the energy losses is expected to depend on their mass. The elliptic flow of charm and bottom also provide a medium coupling of heavy flavor with the QGP. The suppressions of quarkonia...
Strangeness production has been suggested as a sensitive probe to the early dynamics of the deconfined matter created in heavy-ion collisions. Ratios of particle yields involving strange particles are often utilized to study freeze-out properties of the nuclear matter, such as the strangeness chemical potential and the chemical freeze-out temperature. $\rm{d}$+Au data connect between ...
The collision system size dependence of light (anti-)nuclei and (anti-)hypertriton production is investigated using the parton and hadron cascade (PACIAE) model plus dynamically constrained phase-space coalescence (DCPC) model in 10B+10B, 12C+12C, 16O+16O, 20Ne+20Ne, 27Al+27Al, 40Ar+40Ar, 63Cu+63Cu, 96Ru+96Ru, 197Au+197Au, and 238U+238U collisions at √sNN = 200 GeV. The yield ratios of...
High $p_T$ direct photons produced in initial hard scattering are not affected by the colored medium formed in heavy ion collisions. This has been observed in large-on-large ion collisions, where, in contrast, jets and final state hadrons show energy loss, measured via the nuclear modification factor that compares the observed yields to the expected yield from p+p scaled by the number of...
Recent results in heavy ion physics from ATLAS
Quark-gluon plasma (QGP) is a state of matter which exists at extremely high temperatures and densities. Formation of QGP in collisions of heavy relativistic nuclei was predicted by quantum chromodynamics (QCD) and proved by experimental observation of QGP signatures.
One of such signatures is enhancement of baryon production over meson production. This effect was firstly observed by PHENIX...
The relativistic heavy-ion collisions aim to create the matter under high temperature and high density, called Quark-Gluon Plasma, and study its properties. Strange and multi-strange hadrons have a smaller hadronic cross-section than light hadrons, making them a better probe for comprehending the early stages of relativistic heavy-ion collisions. In 2018, isobar collisions,...
The production of light nuclei in relativistic heavy-ion collisions is usually described by the thermal model and the coalescence model. The thermal model suggests that the light nuclei are emitted by a source in local thermal equilibrium with other hadrons and their yields are fixed at chemical freeze-out. However, given that the binding energies of light nuclei are only of the order of a few...
Quantum Chromodynamics (QCD) predicts that at sufficiently high-temperature (T) and/or baryon chemical potential ($\mu_{B}$), normal nuclear matter converts into a de-confined state of quarks and gluons, known as Quark-Gluon Plasma (QGP). A hot and dense medium of quarks and gluons is created in relativistic heavy-ion collisions. The dynamics and collective behavior of such strongly...
Local multiplicity fluctuations are a useful tool to understand the dynamics of the particle production and the phase-space changes from quarks to hadrons in ultrarelativistic heavy-ion collisions. The study of scaling behavior of multiplicity fluctuations in geometrical configurations in multiparticle production can be done using the factorial moments and recognized in terms of a phenomenon...
In the medium of relativistic heavy-ion collisions, dissociation of the
quarkonium and their survival have been studied to understand the properties of Quark Gluon Plasma (QGP). The coupled rates of dissociation and recombination reactions in QGP are commonly solved with
Boltzmann transport equation in which the formation and dissociation
reactions compete. Since the dissociation of newly...
The data on charge balance function in Pb+Pb collisions at center-of-mass energy 2.76 TeV per nucleon pair are analyzed with the HYDJET++ model. For central collisions the width of the charge balance function at low transverse momentum intervals is larger in the model than in data both in relative pseudorapidity and relative azimuthal angle. An approach which takes into account the...
In heavy-ion collisions, a strong magnetic field ($\sim$ 10$^{15}$ T) is expected to be created, which together with the presence of a non-zero vector and axial currents gives rise to a collective excitation in the quark--gluon plasma (QGP) called the Chiral Magnetic Wave (CMW). The experimental signature of the CMW is charge-dependent elliptic flow, $v_{2}$. In particular, the normalized...
The study of event-by-event mean transverse momentum ($p_\mathrm{T}$) fluctuations is a useful tool to understand the dynamics of the system produced in ultrarelativistic heavy-ion collisions. The measurement of higher-order fluctuations of mean-$p_\mathrm{T}$ can help in probing the hydrodynamic behavior of the system and is considered to be a direct way of observing initial-state...