Leveraging its precise vertex reconstruction and advanced particle identification, the LHCb detector offers a unique environment to study spin dynamics and hadronization in high-energy collisions. Measurements of baryon polarization in unpolarized proton-nucleus collisions probe how quark spins contribute to the final-state hadron, providing insight into parton spin transfer and fragmentation...
One of the main physics goals of the Beam Energy Scan (BES) program at RHIC is to study the QCD phase diagram, especially around the phase transition between the quark-gluon plasma (QGP) and hadronic matter. BES Phase-I studied Au+Au collisions from center-of-mass energy ($\sqrt{s_{_{\rm{NN}}}} $) of 7.7 to 62.4 GeV. BES Phase-II extended these measurements in several important ways, one of...
The study of exotic hadrons has long been a topic of great interest for the understanding of Quantum Chromodynamics (QCD). As one of the light exotic hadrons, the structure and constituent quark content of $f_0(980)$ have been debated for decades, with theories suggesting it could be a tetraquark state ($s\bar sq\bar q$) or a hadronic molecule ($K\bar K$). Assuming that the $f_0(980)$ is a...
Measurements in pp and p–A collisions have revealed that small collision systems exhibit most of the signs traditionally attributed to heavy-ion collisions, such as the smooth increase of the strange hadron yields with the collision multiplicity (strangeness enhancement). A key question is how these effects evolve with system size and whether they can be described within a unified...
The D-measure of net-charge fluctuations quantifies the variance of net charge in strongly interacting matter. It was introduced over 20 years ago as a potential signal of quark-gluon plasma (QGP) in heavy-ion collisions, where it is expected to be suppressed due to the fractional electric charges of quarks. Measurements have been performed at RHIC and LHC, but the conclusion has been elusive...
We study the local spin polarization of quarks induced by color-field correlators stemming from the correlation of chromo-Lorentz force and chromo-magnetic polarization or chromo-spin Hall effect in the presence of momentum anisotropy.
Such effects can trigger longitudinal polarization from fluctuating color fields in glasma or quark gluon plasma phases with transverse expansion for...
The study of high-energy collisions of small systems has generated significant discussions about the initial conditions, including the size of the system, needed to generate the Quark-Gluon Plasma (QGP). Results from asymmetric small systems, such as $p$+Au and $p$+Pb, exhibit some QGP-like signatures (e.g., flow and enhancement of strangeness production) but not others (e.g., jet quenching)....
Constituent quark number scaling has been proposed as one of the key signatures of a QGP phase. The flow scaling arises from a quark coalescence picture relevant at intermediate transverse momenta. While at collision energies above 7.7 GeV the NCQ scaled elliptic flow of baryons and mesons aligns very well, the scaling breaks between 4.5 and 3.0 GeV as evidenced by recent STAR measurements. At...
The observation of hyperon polarization in heavy-ion collisions has established spin phenomena as powerful probes of the properties of the quark-gluon plasma (QGP) and the dynamics of strongly interacting matter. Global polarization reflects the medium’s overall vorticity, while local polarization is expected to arise from anisotropic flow–induced vorticities, although current theoretical...
Measurements of light hadron production provide essential insight into final-state effects in ultrarelativistic nuclear collisions. These effects include collective flow in both small and large systems, hadronization via recombination, strangeness enhancement, and modifications arising from cold nuclear matter. Studies of system-size and centrality dependence further constrain the role of...
Exotic particles are those whose internal structure is not well understood and cannot be accurately described by state-of-the-art theoretical models or predictions. Current hypotheses regarding the nature of these exotic particles range from conventional mesons and baryons to multiquark configurations (such as tetraquarks), glueballs composed of valence gluons, and molecularly bound states...
Collective phenomena and the baryon-to-meson ratio in high-energy nuclear collisions provide unique insights into the formation and evolution of the quark--gluon plasma (QGP). For the first time, elliptic ($v_2$) and triangular ($v_3$) flow coefficients of strange hadrons ($\Lambda$ and $K^{0}_{S}$), together with $\Lambda/K^{0}_{S}$ ratios, are measured in light-ion (OO and NeNe) collisions...
The High Acceptance Di-Electron Spectrometer (HADES) [1] installed at the SIS18 accelerator in GSI Darmstadt registers products of heavy-ion collisions (as well as of elementary interactions) at energies of a few GeV per nucleon. The nuclear matter produced in such collisions reaches extreme densities and temperatures [2, 3, 4], comparable to those expected in neutron star mergers [5]....
Most current initial condition models for ultra-relativistic heavy-ion collisions assume an
initial state based on gluon saturation, such as IP-Glasma and EKRT. However, conventional hydrodynamics models rely on an assumption of chemical equilibrium between quarks and gluons, even though the timescales of equilibration remain an open question. Here we test this equilibrium assumption, using...
Ultra-relativistic nuclear collisions create strongly interacting matter at extreme temperatures and energy densities, forming a quark–gluon plasma (QGP). Its space-time evolution is characterized by strong collective expansion, giving rise to anisotropic flow and demonstrating its nearly perfect fluid nature. This anisotropic motion generates local shear and vorticity along the beam...
Thermal dielectrons serve as an ideal thermometer to probe the average temperature of the hot and dense QCD medium created in heavy-ion collisions. Previous measurements over a wide range of collision energies and collision systems exhibit consistent temperature trends, indicating significant contributions from the quark-gluon plasma (QGP). Oxygen-oxygen (O+O) collisions, with an effective...
Hadronic resonances are a valuable tool for studying the strongly interacting matter created in relativistic heavy-ion collisions. Their short lifetimes make them sensitive probes of the late hadronic stage, where competing rescattering and regeneration processes can modify momentum and azimuthal distributions. Rescattering of decay daughters can alter their momenta, preventing the...
The speed of sound $c_s$ in strongly interacting matter encodes the stiffness of the nuclear equation of state (EOS). Recent theoretical work has argued that $c_s^2$ can be extracted experimentally from the logarithmic slope between the mean transverse momentum $\langle p_{T} \rangle$ and charged multiplicity $\langle dN/d\eta \rangle$ in ultra-central collisions. In ultra-central collisions,...
Over fifty years after the first observation of unexpectedly large transverse Λ polarization, the underlying mechanism remains a long-standing puzzle seen across many collision systems, from e⁺e⁻ to proton–nucleus collisions. Only in heavy-ion collisions has this phenomenon been understood in terms of strong vorticity in the Quark Gluon Plasma. In this talk, we present an alternative...
Strangeness enhancement has emerged as a system-spanning trend in pp, pPb, and PbPb collisions. Whether a similar behavior is present in elementary $e^+e^-$ collisions, where the initial state is clean and final-state interactions are minimal, is a key question for disentangling hadronization dynamics from hot-QCD effects. We present a measurement of the kaon-to-pion yield ratio,...
The LHCb experiment collected large samples of $p$O, OO, and NeNe collisions in the summer of 2025. These samples will allow for precise studies of nucleon structure in light ions in the unexplored low-$x$ region. In addition, these samples will allow for probing the onset of QGP production in light-ion collisions. First results from the light-ion run with the LHCb detector will be presented,...
We have developed a relativistic resistive magnetohydrodynamic (RRMHD) model to tackle an important problem of heavy-ion physics: understanding the impact of the strong electromagnetic (EM) fields on the quark-gluon plasma (QGP) medium. Our model simulates the evolution and interaction between charges in the QGP and EM fields. This leads to modifications of electrically charged observables. In...
We present a Fisher–information–based sensitivity analysis of the Chiral Mean Field (CMF) model parameters using neutron star observables as macroscopic probes of dense QCD matter. Building upon the MUSES framework, we developed a workflow that integrates the CMF, Lepton, and QLIMR modules to generate cold, $\beta$-equilibrated equations of state by smoothly merging a CMF core with the SLy...
Studies of strong interactions between hadrons provide a unique opportunity to test Quantum Chromodynamics calculations at nucleon-scale distances. The femtoscopy technique, based on measuring correlations of hadron pairs in momentum space, has proven to be a powerful tool to study interactions involving short-lived particles. While strong interactions among light and strange hadrons have been...
We investigate the equation of state (EoS) for hot and dense hadronic matter within an extended Chiral Mean Field (CMF) model framework that incorporates the interactions of thermally excited mesons, including both non-strange and strange species. In this approach, the in-medium masses of pseudoscalar and vector mesons are evaluated through the explicit chiral symmetry-breaking and...
In relativistic heavy-ion collisions, charged particles are accelerated to nearly the speed of light, and their external electromagnetic fields can be effectively approximated as quasi-real photons. These photons interact with another nucleus via photon-nuclear interactions, producing vector mesons. These vector mesons possess extremely low transverse momentum ($p_T\sim0.1$ GeV/$c$),...
Two-particle femtoscopy provides a powerful tool for studying the spatial-temporal characteristics of particle emission source and final-state interactions in high-energy nuclear collisions. The particle emission source size R, and interaction parameters, such as the scattering length $f_0$ and effective range $d_0$, are key to understanding the freeze-out dynamics in such collisions. In...
High-momentum charged particles originate from the fragmentation and hadronization of partons that undergo hard scattering, and their yields are consequently sensitive to parton energy loss in the QGP. The CMS experiment has recently reported a significant suppression of charged-particle production in oxygen–oxygen (OO) collisions at \sqrt{s_{NN}} = 5.36 TeV, providing a first indication of...
Recent 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 ultrarelativistic energies. In this talk, we present the first measurements of multi-particle cumulants (up to eight-particle) for $v_2$...
Strangeness production has been suggested as a sensitive probe of the early dynamics of the deconfined matter created in heavy-ion collisions. The measurements of the colliding energy dependence of (multi-)strange baryon-to-meson ratios can provide us with insights into the hadronization mechanism, which will contribute to the search for the energy threshold of the production of the Quark...
Femtoscopic techniques provide unique insights into particle production mechanisms in hadron collisions, as well as interactions between short-lived hadrons. The LHCb detector's excellent momentum resolution makes it well-suited for studies of femtoscopic correlations. In addition, LHCb's vertex reconstruction and particle identification capabilities allow for studies of femtoscopic...
We develop a relativistic framework for resistive magnetohydrodynamics for a two-component plasma composed of oppositely charged massless particles. Starting from the Boltzmann–Vlasov equation, the 14-moment method is used to derive coupled evolution equations for the charge–diffusion current and the shear–stress tensor. The formulation captures nonlinear feedback between electromagnetic...
Chiral symmetry in QCD is expected to be partially restored at high temperature and/or baryon density, where the chiral condensate that generates most hadron masses decreases. A key manifestation of this restoration is the degeneracy in mass of chiral partners such as vector and axial-vector mesons. To identify these effects, it is essential to achieve a precise understanding of the...
We formulate a hadron resonance gas model with density-dependent mean field interactions and a generalized excluded volume prescription. The framework, implemented within the open-source Thermal-FIST package, provides a unified description of the hadronic phase in heavy-ion collisions and neutron star matter. We also discuss the interplay of constraints from lattice QCD susceptibilities,...
Quantum kinetic theory (QKT) of relativistic fermions is one of useful theoretical frameworks to track non-equilibrium evolution of spin transport albeit in weakly coupled systems. Except for the quantum corrections, characterized by the gradient expansion in phase space, from the imaginary part of (retarded and advanced) self-energies responsible for the spin-orbit interaction in collisions,...
The new sPHENIX collider detector experiment features a unique tracking system capable of streaming readout, enabling the collection of very large, unbiased p+p datasets previously not available at RHIC. In RHIC Run-24, sPHENIX recorded over 100 billion p+p collisions at 200 GeV in this readout scheme, and is collecting additional p+p data at the end of Run-25 with an even higher fraction of...
It has been challenging to quantitatively understand the stopping of incoming nucleons in nuclear collisions, and recently it has been proposed that comparing the baryon stopping with electric charge stopping can help address the question. In this study [1] we focus on the B/Q×Z/A ratio, which can strongly depend on rapidity although its value is one for the full phase space. We find that this...
The NA61/SHINE experiment at the CERN SPS performs a systematic scan in collision energy and system size to study the onset of deconfinement and the mechanisms of strangeness production in strongly interacting matter. This contribution presents recent results on both charged and neutral hadron production in nucleus–nucleus collisions.
Hadron production results, including the $K^{+}/\pi^{+}$...
Understanding hyperon-nucleon interactions is crucial for describing strange nuclear matter and for resolving the hyperon puzzle in neutron stars. Three-body forces are expected to play a key role in this context [1]. In this work, we report the measurement of the p-p-$\Lambda$ three-particle correlation functions in Au+Au collisions at $\sqrt{s_{NN}}$=3 GeV. At this beam energy, the system...
The Lorentz-boosted electromagnetic fields of relativistic heavy ions serve as intense sources of linearly polarized quasi-real photons. Under the $s$-channel helicity conservation hypothesis, a coherently photoproduced vector meson inherits this polarization, leading to a characteristic second-harmonic ($cos2\phi$) modulation in the azimuthal distribution of its decay products. Such...
Chirality is a fundamental element in the construction of the Standard Model and a key feature for understanding non-perturbative aspects of Quantum Chromodynamics (QCD). Chiral Magnetic Effect (CME) provides a unique access for experimental probe of chirality in heavy ion collisions. Recent measurements from Beam Energy Scan II data by the STAR Collaboration demonstrate very interesting beam...
Due to their large masses, heavy quarks (charm and beauty) are predominantly produced in the initial hard-scattering processes. They serve as effective probes of the quark–gluon plasma (QGP) expected to form in heavy-ion collisions, as they traverse and interact with the constituents of the medium throughout its entire evolution. In these collisions, the measurement of the angular correlations...
Radial and anisotropic flow are key observables for probing the expansion dynamics of the quark-gluon plasma (QGP). The first measurement of transverse momentum–dependent radial flow fluctuations, v0(pT), in Pb+Pb collisions is presented. The $v_0(p_T)$ observable exhibits three key features: (i) long-range correlations in pseudorapidity, (ii) factorization in $p_T$, and (iii) a...
We report the first measurements of two-particle transverse momentum correlations for mid-rapidity charged particles in Au+Au collisions at $\sqrt{s_{\rm NN}} =$ 3.0, 3.2, 3.5, 3.9, 4.5, and 7.7 GeV recorded by the STAR experiment.The results are compared with previous STAR measurements from the Beam Energy Scan Phase I (BES-I) and with transport model calculations. The measured two-particle...
Understanding the expansion dynamics and transport properties of the quark--gluon plasma (QGP) is one of the central goals of heavy-ion collision experiments. The newly proposed observable $v_0(p_T)$ [1], which is directly sensitive to $p_T$-differential fluctuations of radial flow, has been measured by the LHC experiments [2,3] and has been suggested as a sensitive probe of the medium's bulk...
The Glasma is produced in the pre-equilibrium stage of high-energy heavy-ion collisions within the Color Glass Condensate framework. These strong, classical, out-of-equilibrium gluon fields significantly influence the dynamics of heavy quarks, which are created early in the collision. Our study shows that the azimuthal correlations of $c\overline{c}$ and $b\overline{b}$ pairs are strongly...
The Chiral Magnetic Effect (CME)—a QCD-anomaly–driven charge separation in the strong magnetic fields of non-central heavy-ion collisions—remains extremely difficult to isolate because flow-related backgrounds, especially from resonance decays, can mimic CME-like correlations. To address this weak-signal in a complicated background problem, we explore Transformer-based Artificial Intelligence...
Lattice QCD calculations predict the existence of a crossover between a deconfined, thermalised partonic phase and the hadronic phase under conditions of exact baryon–antibaryon symmetry. Fourth-order baryon-number susceptibilities show significant deviations from the hadron resonance gas across the crossover, carrying information on residual criticality associated with the chiral phase...
A significant global spin alignment ($\rho_{00}$) signal for $\phi$-mesons was observed by the STAR collaboration in Au+Au collisions using the data from the first phase of the Beam Energy Scan at RHIC (BES-I) [1]. Conventional physical mechanisms which contribute to $\rho_{00}$ fail to explain the observed signal; however, it may be attributable to the presence of a $\phi$-meson strong force...
Baryon ($\mu_B$), electric charge ($\mu_Q$) and strange quark ($\mu_S$) chemical potentials, and temperature ($T$) are fundamental thermodynamic parameters characterizing QCD matter under extreme conditions. Their differentials ($\Delta\mu_B/\Delta\mu_Q$, $\Delta\mu_S/\Delta\mu_Q$) provide insight into the system’s constituent correlation, response, and trajectory in the multidimensional (4D)...
We present, for the first time, the charmed hadron $p_T$–differential radial flow $v_0(p_T)$, within a Langevin transport framework that incorporates event-by-event fluctuations. We propose $v_0(p_T)$ of heavy quarks as a novel and sensitive observable for probing the properties of the Quark–Gluon Plasma (QGP). This observable exhibits a pronounced sensitivity to the interaction strength...
The study of charm-quark production and hadronisation provides crucial insights into the mechanisms of Quantum Chromodynamics (QCD) at the interface between the perturbative and non-perturbative regimes. Differential measurements of jets containing charm hadrons further shed light on QCD processes such as parton-shower evolution and hadronisation. In particular, angular correlations between...
It has recently been realized that in the ultra-central heavy-ion collisions, mean transverse momentum of hadrons contains the information of the fundamental thermodynamic properties of quark-gluon plasma (QGP). In particular, in nucleus-nucleus collisions, the linear correlation between the mean transverse momentum and the charged multiplicity is attributed to the QCD speed of sound, which...
Ultra-relativistic heavy-ion collisions create a unique environment for studying the quark–gluon plasma (QGP). In non-central collisions, the large initial orbital angular momentum can be transferred to the medium as vorticity, inducing a global polarization of produced particles. Furthermore, the strong initial magnetic field generated in heavy-ion collisions can contribute to the global...
This talk presents new ATLAS results that probe the mass and system-size dependence of parton-medium interactions using heavy-flavor jets in Pb+Pb collisions and hard-process correlations in O+O collisions. The first part reports measurements of b-tagged jets and events with multiple jets recoiling against a photon in Pb+Pb collisions. These measurements place strong constraints on the...
We present recent STAR measurements of the newly proposed radial flow fluctuation coefficient, $v_{0}(p_{T})$, for strange and multi-strange hadrons in heavy-ion collisions at RHIC. The $v_{0}(p_{T})$ of strange and multi-strange hadrons is of great interest because these particles are less affected by late-stage hadronic interactions, making them good probes of the early partonic stage. The...
Although calculations of QCD thermodynamics from first-principle lattice simulations are limited to zero net-density due to the fermion sign problem, it is possible to extend the equation of state (EoS) to finite values of the $\mu_B, \mu_Q, \mu_S$ chemical potentials via expansions around zero chemical potentials. Thanks to a new method based on a T'-expansion scheme, it was possible to...
The STAR Collaboration reported a significant $\phi$-meson global spin alignment ($\rho_{00}$) signal in Au+Au collisions at $\sqrt{s_{NN}}\leq62$ GeV by measuring the one dimensional (1D) polar angle distribution of $\phi$-meson daughters with respect to the orbital angular momentum direction of the collision system [1].
This talk summarizes methodological developments from a recent paper on...
In heavy-ion collisions, azimuthal correlations probe collective phenomena in the hot and dense medium formed, known as the Quark–Gluon Plasma (QGP). In small collision systems, similar correlations may arise from final-state effects or from initial-state parton correlations. The LHCb experiment has a unique capability to study particle correlations in high-energy hadron collisions at forward...
Heavy quarks (charm and beauty) are 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 theory. Furthermore, the associated production of two charm hadrons in a single collision probes the dynamics of multiparton interactions, distinguishing between...
Charm quarks, produced in the earliest stages of high-energy heavy-ion collisions due to their large masses, are sensitive to the full evolution of the strongly interacting medium and serve as unique probes of its collective properties. Measuring the elliptic flow ($v_{2}$) of open-charm hadrons across different collision systems provides crucial insight into the onset and strength of...
We present a study of net-proton number fluctuations in central Au+Au collisions at $\sqrt{s_{\mathrm{NN}}} = 7.7 - 200$ GeV using viscous hydrodynamic simulations. Proton and antiproton fluctuations are evaluated on the hydrodynamic freeze-out hypersurface via a Cooper–Frye procedure adapted to an interacting hadron resonance gas. Effects of limited experimental acceptance and global charge...
With the large data sets of $e^+e^-$ annihilation at the $J/\psi$ and $\psi(3686)$ resonances collected by the BESIII experiment, multi-dimensional analyses utilizing polarization and entanglement can provide new insights into the production and decay properties of hyperon-antihyperon pairs. In a series of recent studies conducted at BESIII, significant transverse polarization of the...
The $\Lambda$ binding energy difference between $\rm ^4_{\Lambda}H$ and $\rm ^4_{\Lambda}He$, which is called the charge symmetry breaking in the ground states of a pair of A = 4 hypernuclei, was measured to be $\Delta B_{\Lambda}^4(0_{g.s.}^{+})\approx 350~$keV in nuclear emulsion experiments in the 1970s. In the 2015 and 2016 experiments from J-PARC and A1 collaboration, the binding energy...
The description of heavy quarks inside the QGP medium, especially at low momenta, remains challenging from first principles, due to large coupling strength and gluon occupation numbers. An alternative way to formulate a description in terms of perturbative degrees of freedom is the interaction of the heavy quarks with the collective excitations of the medium in the form of phonons. This...
Among the various light-flavoured species produced in heavy-ion collisions, light (anti)nuclei present a unique challenge to hadronization models due to their small binding energies compared to the chemical freeze-out temperature of the system. The statistical hadronization model describes their production as part of the same thermal framework that successfully reproduces the yields of all...
Heavy quarks serve as pristine probes of the transport properties and hadronization dynamics of the quark–gluon plasma (QGP) created in high-energy nuclear collisions. A key challenge in this context is to embed the interactions of heavy quarks in the expanding medium compatible with the strong-coupling nature of the QGP, and thus to unravel the underlying microscopic mechanisms. Toward this...
Directed flow $v_1$ has been used to probe early dynamics in high-energy nuclear collisions. The vector meson $\phi(s \overline{s})$, with a mass comparable to that of light baryons, exhibits a small interaction cross section with other hadrons. Therefore, the measurement of $\phi$-meson directed flow $v_1$ provides clean access to the early collision dynamics and the production mechanisms of...
The dynamics of heavy quarks in quark-gluon plasma (QGP) formed in heavy ion collisions provide a unique window to characterize its properties. Existing approaches to describe heavy quarks in medium rely either on quasiparticle-based models of QGP, or on assuming that the momentum transfer from the medium follows Gaussian statistics. However, neither of these assumptions can be taken for...
The discovery of exotic muonic atoms, including muonic antihydrogen and muonic kaon atoms, constitutes a milestone in our ability to make and study new forms of matter. The unique environment of relativistic heavy-ion collisions, characterized by the abundant production of muons alongside other charged particles, provides a promising platform for the formation and detection of these exotic...
We explore the properties of strongly interacting matter at finite temperature and baryon chemical potential as created in relativistic heavy-ion collisions, focusing on the QCD phase structure probed via dilepton observables. The equilibrium description of the non-perturbative quark–gluon plasma (QGP) is realized within the Dynamical QuasiParticle Model (DQPM), which reproduces lattice QCD...
Nuclear clusters and hypernuclei serve as essential probes of the strong interaction.
The production of clusters and hypernuclei in heavy-ion collisions is an intricate process that involves the formation of few-body bound systems within a dynamic many-body environment. Accurate knowledge of their static properties is essential input for transport approaches, as it directly determines their...
Recently, a new equation of state based on the two-dimensional T'-expansion scheme with a parametrizable critical point from the 3D Ising model was released [1]. It allows to produce a family of equations of state which can be used to study the effect of the critical point on the QCD phase diagram, crucial to infer its existence and location from experimental results. Employing the newly...
The charm quark is formed almost exclusively during the initial stages of the collision, and a significant fraction of the charm quarks fragment into the $D^{0}$ meson, the lightest open-charm hadron. We can gain insights into the interactions between the charm quark and the quark-gluon plasma (QGP) medium by studying the production and the flow of $D^{0}$ mesons in heavy-ion collisions. We...
In relativistic heavy-ion collisions, a large number of light nuclei can be produced. Studying the production mechanism of light nuclei can help us understand the evolution process of relativistic heavy-ion collisions. There have been quite a lot of studies on stable light nuclei, while research on unstable light nuclei is still relatively lacking. Unstable light nuclei are fragile resonance...
Generative artificial intelligence (AI) has been transforming industry and science. sPHENIX, a new experiment at RHIC, has been at the cutting edge in adopting innovative generative AI to accelerate simulation, reconstruction, and analysis in a robust manner. In this talk we will highlight three recent works on (1) diffusion model based full detector full event heavy ion collision simulation...
At the LHC, matter and antimatter are produced in equal abundance, making it a true antimatter factory. Among the many antiparticles observed, antinuclei are of particular interest, as their production mechanism in high-energy hadronic collisions remains a topic of active discussion and fascination. The ALICE Collaboration has previously measured, for the first time, the production of...
We introduce a model-independent mechanism to merge two (or more) equations of state (EoS) by treating them as a two-fluid statistical mixture in the Grand Canonical Ensemble. The merged grand-potential density $\omega(T,\mu_B)$ is built directly from the input EoS, and the fluid fraction is fixed by minimizing $\omega$ at fixed $(T,\mu_B)$. Thermodynamic consistency is enforced across all...
We derive the leading modifications to transverse momentum broadening and medium-induced gluon spectrum in flowing matter for the case of a heavy flavor quark. We show that the broadening and radiation patterns acquire a new directional dependence arising from the interplay between the quark mass and the medium flow — an effect absent in the massless case. Consequently, the dead-cone effect is...
Measurements of identical pion femtoscopy offer insights into collision dynamics, such as collective expansion, geometry of the collision zone at freeze-out, final state interactions, etc. In addition to the quantum interference and Coulomb interactions among the pion pairs, Coulomb interactions between the pair and the net positive charge in the emitting source affect the final correlation...
The study of strangeness production in small collision systems provides crucial insights into the mechanisms governing particle production at the LHC. Recent observations in proton–proton (pp) and proton–lead (p–Pb) collisions have revealed features reminiscent of those seen in heavy-ion collisions, such as collective-like behaviour and strangeness
enhancement, which appear to scale with...
Particle production at LHC energies arises from the interplay between hard and soft QCD processes and is sensitive to non-linear QCD evolution in the initial state. In July 2025, the LHC delivered short light-ion runs, pO, OO, and Ne$-$Ne collisions, providing a unique opportunity to bridge the gap between proton$-$proton and heavy$-$ion collisions. These systems allow us to study and...
Ultra-peripheral collisions provide a unique environment to study pomeron- and photon-induced reactions with heavy nuclei. These interactions can produce a wide range of final state particles, from light vector mesons to heavy quarkonia, and probe potentially exotic phenomena. With a fast and flexible DAQ, full particle ID, and the ability to reconstruct very low pt particles, LHCb is uniquely...
Strangeness production is a key signature of the formation of a hot and dense medium in heavy-ion collisions. Hybrid approaches combining transport theory and hydrodynamics within the core–corona framework have been successful in describing this enhancement.
At the same time, collective behavior and strangeness enhancement have also been observed in small systems such as proton–proton...
Heavy flavor (charm and bottom) production is a unique probe for testing perturbative Quantum Chromodynamics (pQCD) and for investigating the transport properties of nuclear matter. The identification of heavy flavor signals remains one of the most challenging measurements in collider experiments due to their extremely low production rate and substantial background contributions. The...
The $\phi$ meson is a unique probe of strange quark dynamics in high-energy nuclear collisions. The $\phi$ meson's mass lies at the threshold between perturbative and nonperturbative QCD. Consequently, $\phi$ production provides sensitivity to both regimes. In heavy-ion collisions, $\phi$-meson production is senstive to strange-quark coalescence in quark-gluon plasma. The $\phi$ meson's...
Light hadrons constitute the bulk of particle production in heavy-ion collisions. Its properties, such as the production cross-sections of different hadron species or their average transverse momentum, are sensitive to both collective phenomena and the initial state of heavy-ion collisions. Bulk physics measurements in small collision systems can reveal the interplay between initial- and...
Charmonium mesons are bound states formed by a charm quark and its antiquark ($c\bar{c}$). The creation of the heavy charm–anticharm pair results from a hard partonic scattering that can be described within perturbative QCD, whereas the subsequent hadronization into a bound state is governed by non-perturbative QCD dynamics. Therefore, the study of charmonium production provides a key probe of...
Transverse spherocity is an event-shape observable that quantifies the azimuthal distribution of transverse momentum, enabling a clean separation between jetty-like (low spherocity) and isotropic (high spherocity) final states. By using event topology with spherocity, one can disentangle soft, collective-dominated particle production from hard, jet-driven processes without relying solely on...
Quantum Chromodynamics (QCD) predicts the existence of gluonic bound states known as \textit{glueballs}, composed entirely of gluons. Their experimental identification remains elusive due to possible mixing with nearby scalar mesons. The high-statistics proton--proton data at $\sqrt{s} = 13.6~\mathrm{TeV}$ recorded with the ALICE detector provide a new opportunity to explore such states. In...
In non-central heavy-ion collisions, due to a non-zero impact parameter, a substantial angular momentum is produced. Through spin–orbit coupling, this angular momentum can induce quark polarization, which may subsequently manifest as a net polarization of the produced hyperons and vector mesons. In contrast, the hyperon and vector meson polarization in pp collisions provides an essential...
Measurement of resonances provides a tool to study the hadronic phase, the phase between chemical and kinematic freeze-out in the evolution of the quark-gluon plasma (QGP). Baryonic resonances, such as $\Xi(1530)^0$ (net-strangeness = -2) with a relatively long lifetime ($\sim$ 22 fm/$c$), serve as key probes to investigate the effects of rescattering and regeneration in the hadronic phase by...
Collisions of light ions (OO, Ne–Ne, and pO) at the LHC bridge the gap between small and large systems, offering new insight into the onset of collective behavior and hadronic medium effects. Hadronic resonances, owing to their lifetimes comparable to the hadronic phase, serve as sensitive probes of late-stage dynamics where re-scattering and regeneration compete.
We present measurements of...
Understanding the event geometry in high-energy collisions is essential for exploring the underlying particle production mechanisms. In this work, we employ transverse spherocity as a novel tool to classify events by their geometrical structure and analyze global observables of (multi-)strange and charged particles in oxygen-oxyegn (O-O) and neon-neon (Ne-Ne) collisions at $\sqrt{s_{NN}}$ =...
We employ a (3+1)-dimensional hydrodynamic framework to investigate the polarization of Λ hyperons in heavy-ion collisions at √sₙₙ = 200 GeV. Our findings reveal a pronounced sensitivity to the choice of initial-state modeling and the viscous properties of the quark–gluon plasma. The model successfully reproduces key hadronic flow measurements and forecasts non-trivial azimuthal modulation...
The production of light antinuclei with mass number A>2 in cosmic rays has long been regarded as a promising indirect signature of dark matter annihilation in the Galaxy, owing to the extremely low expected astrophysical background. A precise understanding of these background contributions, arising from interactions of primary cosmic rays with the interstellar medium, is therefore essential....
At the LHC, the ALICE experiment has observed that the yield ratios of strange to non-strange hadrons increase with charged-particle multiplicity at midrapidity, following a smooth evolution across collision systems, spanning over three orders of magnitude in multiplicity and saturating in central Pb–Pb events. Various models have been proposed to explain the origin of strangeness production...
Balance function (BF) of strange baryons is sensitive to the production and transport of strange quarks and their hadronization to strange baryons during the evolution of the system formed in nuclear collisions. It is also sensitive to quark diffusion in the hot and dense QCD matter as well as to the strangeness and baryon susceptibilities.
In this work, measurements of the $\Lambda$...
The enhancement of the strange baryon-to-meson yield ratio at intermediate transverse momentum ($p_{\rm T}$) observed by ALICE across small to large collision systems is usually attributed to collective radial flow and quark recombination effects. Nevertheless, it remains under discussion whether jet fragmentation also contributes to the observed enhancement, as strange particles in the...
The chromo-magnetic monopoles (CMM), emergent topological excitations of non-Abelian gauge fields carrying chromo-magnetic charge, have long been postulated to play an important role in the vacuum confinement of quantum chromodynamics (QCD), the deconfinement transition at temperature $T_c\approx 160\rm MeV$, as well as the strongly coupled nature of quark-gluon plasma (QGP). While such CMMs...
Strangeness production serves as a powerful probe of the properties of the hot and dense strongly interacting medium created in ultra-relativistic heavy-ion collisions. The enhancement of strange particle yields has long been considered a key signature of the formation of the quark-gluon plasma (QGP). Among strange hadrons, the $\phi$ meson, composed of an $s\bar{s}$ quark pair, plays a...
Heavy quarks, i.e., charm and beauty, in proton-proton collisions at the LHC are mainly produced in hard-parton scatterings at the early stages of the collisions. Owing to the large masses of the charm and beauty quarks compared to the QCD scale parameter ($\Lambda_{\rm QCD}~\sim$ 200 MeV), their production can be described using perturbative quantum chromodynamics (pQCD) calculations. During...
Identical-particle femtoscopy is a powerful tool to probe the space–time structure of the particle-emitting source created in relativistic heavy-ion collisions, through correlations of particle pairs at small relative momenta. Femtoscopic correlations measured by ALICE with Run 3 data for both identical charged pions and protons in OO and Ne--Ne collisions at $\sqrt{s_{\mathrm{NN}}} =...
Investigations involving the event-by-event fluctuations of conserved quantities, like net charge, net baryon number, and strangeness in heavy-ion collisions, provide insights into the properties of QGP and the phase diagram of strongly interacting matter. Event-by-event fluctuations of net-electric charge in pp collisions at $\sqrt{s} = 13$ and $13.6$ TeV and for OO, Ne--Ne, and Pb--Pb...
Since the formation of nuclear clusters, the probing of the nuclear matter equation of state, and the interpretation of hadron correlations at beam energies above 1 GeV all involve strong dynamical correlations and relativistic effects, a covariant
$N$-body dynamical framework becomes essential for a consistent theoretical description.
In this talk, we will present our recent work on a...
The production of identified charged particles ($\pi^{\pm}$, $K^{\pm}$, $p(\overline{p})$) in Pb$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}} = 5.02~\mathrm{TeV}$ is investigated using the EPOS4 model. Two configurations are examined: EPOS4 with and without the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) hadronic transport, allowing isolation of late-stage hadronic effects....
Isospin symmetry, a fundamental feature of the strong interaction, predicts similar production rates of charged and neutral kaons in high-energy collisions. However, recent measurements by NA61/SHINE indicate an excess production of charged over neutral kaons, suggesting significant isospin symmetry breaking that challenges the expectation, and the underlying origin of this effect remains...
Balance functions have been extensively used to elucidate the time evolution of quark production in heavy-ion collisions. Early models predicted two stages of quark production, one for light quarks and one for the heavier strange quark, separated by a period of isentropic expansion. This led to the notion of clocking particle production and tracking radial flow effects, which drive the...
Anisotropic flow measurements in heavy-ion collisions are sensitive to the spatial distribution of the initial state and to the transport properties of the quark--gluon plasma, such as the shear viscosity to entropy density ratio ($\eta/s$). Hydrodynamic models provide a successful description of flow observables over a wide centrality range, yet deviations from data are observed in...
The strange quark is the third lightest quark. Particles containing with strange quarks can be produced easily and quickly via the strong interaction but decayed much more slowly through the weak interaction. Based on his newly well-developed four-element theory of nature, the author has recently developed a new two-flavor (up and down) multi-excitation (ground and excited states) quark...
Light-ion collisions offer a unique opportunity to investigate system-size scaling in relativistic heavy-ion collision dynamics. Using the AMPT model, we study O–O and Ne–Ne collisions at 5.36 TeV and 200 GeV to examine charged-particle production, strangeness enhancement, and collective flow. By comparing systems of similar mass but different nuclear structure, we explore the sensitivity of...
Event-by-event mean transverse momentum fluctuations of relativistic charged particles produced in Pb--Pb collisions at $\sqrt s_{NN} = $ 5.36 TeV are studied in terms of normalized two-particle correlator $\sqrt{C_{m}}/\langle \langle p_{T} \rangle \rangle$. Data collected using the ALICE detector during Run 3 are analyzed for this purpose and the results are compared with those reported...
The production of strange hadrons in high-energy collisions provides insight into hadronization, parton fragmentation, and nuclear effects. While strangeness enhancement has been linked to quark-gluon plasma formation in heavy-ion collisions, recent observations in small systems challenge conventional hadronization models. In this context, proton–nucleus measurements further probe the...
In the Kaluza–Klein model, where one extra compactified spatial dimension is added to usual spacetime, one can consider hadronic states emerging from extra dimensional excitations. These can be associated with e.g., strangeness or higher mass states appearing in the nuclear equation of state, with a non-trivial modification to the speed of sound, especially in the...
Beauty quarks, produced in the initial hard scatterings of heavy-ion collisions, are sensitive to the entire evolution of the quark–gluon plasma (QGP) and thus serve as excellent probes of its properties. Since beauty quarks are detected through their hadronic decays, understanding both their production and subsequent hadronization is essential if we want to use them as reliable QGP probes....
As one of the potential candidates for dark matter, the dark photon ($\rm{A}^{'}$) could act as a mediator between dark matter particles, analogous to the photon ($\gamma$) in the Standard Model, which mediates electromagnetic interactions. The dark photon could be detected through its kinetic mixing with the QED photon, with the strength of this coupling suppressed by a factor labeled...
Understanding the bulk properties of matter produced in heavy-ion collisions is crucial for probing the dynamics and phase transitions of Quark-Gluon Plasma. We present measurements of $\pi^{\pm}$, $K^{\pm}$, $p$, $\bar{p}$, $\Lambda$, $\bar{\Lambda}$, $\Xi$ and $\bar{\Xi}$ ̅production in Ru+Ru and Zr+Zr collisions at $\sqrt{s_{NN}}=200$ GeV using the STAR detector. Transverse momentum ($p_T$)...
Short-lived resonances provide valuable insight into the dynamics and properties of the hadron gas phase that forms after hadronization. Since the resonance lifetime is comparable to that of the hadron gas phase, their measured yields are affected by the competing rescattering and regeneration effects. These can be studied experimentally by measuring the yield ratios of resonances to their...
The ALICE Collaboration has observed the $\Omega(2012)$ baryon via its decays to $\Xi^{-}K^{0}_{S}$ in high-multiplicity proton-proton collision at $\sqrt{s}=13$ TeV. This observation, which has a significance of 15 sigma, corroborates the discovery of this particle by Belle in 2018. The measured mass and width values are consistent with those reported by Belle, confirming that the Omega(2012)...
Charmonium is a bound state of a charm and an anti-charm quark and its production process can be factorized into two stages: the heavy quark production and the formation of the bound state. The former happens within initial hard parton-parton scatterings with large momentum transfers, and can be well described by perturbative quantum chromodynamics (QCD). The second one, which involves long...
The sPHENIX experiment at RHIC, commissioned in 2023, provides large pseudorapidity coverage and full azimuthal acceptance, enabling detailed studies of collectivity in small-collision systems. Data were collected in proton–proton collisions at √s = 200 GeV in 2024. In this poster, we present the current status of two-particle correlation analyses in proton–proton collisions, using silicon...
The analysis of the azimuthal-angle correlation between $\rm{D^{0}}$ mesons and charged particles is important for studying charm-quark production, which occurs in the early stages of high-energy collisions via hard scattering. After their production, charm quarks undergo a fragmentation process which results in a spray of hadrons after hadronization, quite collinear to the charm quark at high...
The study of collective phenomena in high-energy nuclear collisions provides crucial insights into the formation and evolution of the quark–gluon plasma (QGP). The transverse momentum–dependent isotropic flow observable, $v_{0}(p_{T})$, probes radial flow fluctuations and their evolution from small to large systems, providing sensitivity to the medium’s transport properties. Using data...
The collective expansion of Quark-Gluon Plasma (QGP) is characterized by distinct experimental signatures, such as mass ordering$^{[1]}$ of hadron anisotropic flow coefficients ($v_n$) and the Number of Constituent Quarks (NCQ) scaling$^{[2]}$. This poster aims to investigate these key signatures in small collision systems by measuring the anisotropic flow ($v_n$) for identified particles...
Recent measurements of charm-baryon production at midrapidity in small collision systems show a baryon-to-meson ratio significantly higher than that measured in e+e- and e-p collisions. These results indicate that the charm-baryon production in hadronic collisions is not fully understood and suggest a non-universality of fragmentation functions among different collision systems. Models that...
In this poster, we present measurements of $J/\psi$ meson production in $p$+$p$ collisions at $\sqrt{s}=510$ GeV as a function of event activity. The $J/\psi$ mesons are reconstructed via their dielectron decay channel at mid-rapidity $(|y|<1)$ for the transverse-momentum range $4<p_{T}<12$ GeV/$c$. We observe a faster-than-linear increase in $J/\psi$ production with respect to the...
The long-range near-side correlation and collective motion have been observed in proton-proton (pp) collisions, suggesting that a hot and dense medium could be produced even in small systems such as pp and p--Pb collisions. One of the common observables used to quantify collective motion is the second-order flow coefficient, $v_2$, which has been observed in both the light-flavor and open...
The sPHENIX experiment at RHIC is designed to explore the properties of strongly interacting matter through precision measurements of global observables in relativistic ion collisions, using full-azimuth calorimetry and high-resolution silicon tracking. This talk presents final results for measurements of the transverse-energy density (dE$_T$/dη) and charged-hadron multiplicity density...
Dileptons, being electromagnetically decoupled from the strongly interacting medium, are key probes of the thermal and chemical evolution of the Quark-Gluon Plasma (QGP) and the hadronic matter. In the intermediate mass range ($m_\phi < m_{ee} < m_{J/\psi}$), they primarily originate from the thermal radiation of the QGP and semi-leptonic decays of heavy flavor mesons. Disentangling these...
Hypernuclei are nuclei containing both nucleons and hyperons. Studying
their properties provides essential insights into the hyperon–nucleon interaction — a key component of the strong force that remains poorly understood. The lightest known hypernucleus is the hypertriton ($^3_{\Lambda}$H). In recent years, ALICE has performed the most precise measurements of the $^3_{\Lambda}$H lifetime and...
Collectivity in small collision systems at both RHIC and the LHC have attracted considerable attention regarding the origin of azimuthal anisotropy and the light nuclei structure. Recent measurements have established a geometry-driven picture through the comparison of $v_2\{2\}$ and $v_2\{4\}$ in $d$+Au and $^{16}$O+$^{16}$O collisions at $\sqrt{s_\mathrm{NN}}=200$ GeV at STAR, underscoring...
Recent measurements of charged hadron azimuthal anisotropies in both asymmetric and symmetric small collision systems have far-reaching implications for the origins of final state momentum anisotropy driven by nucleonic as well as sub-nucleonic fluctuations present during the initial state. The creation of Quark-Gluon Plasma (QGP) in small collision systems is a topic of active research, given...
Baryon number is one of the most rigorously tested conserved quantities in physics. Traditionally, it is thought to be carried by valence quarks, but this view lacks experimental confirmation and is not derived from Quantum Chromodynamics. In the 1970s, an alternative theory was proposed, suggesting the existence of a non-perturbative Y-shaped structure in the gluon field of baryons, known...
The nature of the high invariant mass region ($M_{K^{+}K^{-}} > 1.1~\mathrm{GeV}/c^{2}$) in coherent $K^{+}K^{-}$ photoproduction in ultra-peripheral heavy-ion collisions (UPCs) has remained an unresolved question in physics. Previous ALICE measurements have shown nontrivial structures in this region, but the underlying production mechanisms are stil under debate. The relative contributions...
Anisotropic flow is expected to generate local vorticities along the beam direction, which in turn leads to local polarization. While local polarization of hyperons has been observed at RHIC and the LHC, current theoretical models cannot completely explain data observed in experiments. Some theoretical calculations suggest that the local polarization of hyperons can be from mechanisms other...
Charm-baryon production measurements in proton--proton (pp) collisions at the LHC provide valuable input for understanding charm-quark hadronization mechanisms and testing perturbative quantum chromodynamics (QCD) based calculations. Recent measurements show baryon-to-meson ratios significantly higher than those measured in $\mathrm{e}^{+}\mathrm{e}^{-}$ collisions, suggesting a...
Heavy quarks, such as charm and beauty, are produced in hard-scattering processes occurring in the early stages of the collisions at the LHC. Therefore, the production of heavy-flavour hadrons in proton–proton (pp) collisions provide an important test of quantum chromodynamics (QCD). A significant enhancement of the \Lambdac/\Dzero\ production yield ratio was observed in pp collisions compared...
Coherent vector meson photoproduction in ultraperipheral heavy-ion collisions (UPCs) provides a powerful probe of the nuclear gluon structure at small Bjorken-$x$. Vector mesons with different masses exhibit varying sensitivities to nonlinear QCD dynamics: lighter mesons probe lower energy scales and are therefore more sensitive to gluon saturation and nuclear shadowing effects. Among them,...
Central Exclusive Production (CEP) refers to a class of processes in which two protons interact through the exchange of colorless objects, such as photons or pomerons, resulting in the production of an isolated hadronic system in the central region, while both protons remain intact. In this analysis, CEP events are studied in proton–proton collisions at $\sqrt{s} = 510~\mathrm{GeV}$ recorded...
Using the finite-temperature Chiral Mean Field (CMF) model within the MUSES framework—where the baryon octet and decuplet, including strange baryons, interact via meson fields and are treated at finite 𝑇 through Fermi integrals—we extend the particle content by adding species not included in CMF as a non-interacting ideal gas of PDG-listed hadrons and resonances, explicitly incorporating...
We present a comprehensive study of the momentum-differential radial-flow fluctuations $v_0(p_T)$, which quantifies event-by-event correlations between the mean transverse momentum and the spectral shape, over the full measured range up to 10 GeV/$c$. Using a Bayesian-calibrated multistage hydrodynamic framework, we identify a universal scaling of $v_0(p_T)$ at low $p_T$, revealing a robust...
I present a comprehensive investigation of hadron production dynamics in high-energy collisions, ranging from proton-proton to lead-lead, utilizing a non-extensive statistical framework and data from the ALICE experiment at the LHC. Analyzing identified hadron spectra – including light and charmed species – we demonstrate the power of the Tsallis thermometer to map out the thermal...
The search for quark-gluon plasma in small collision systems has led to renewed interest in the internal structure of nuclei. This study explores the impact of alpha-clustering – the formation of ⁴He nuclei within larger nuclei – on collective flow in oxygen-oxygen (O-O) collisions at the Large Hadron Collider. Utilizing a sophisticated hybrid hydrodynamic model, we demonstrate that...
In ultra-relativistic heavy-ion collisions, large rates of γγ processes occur through the interaction of the large electromagnetic fields of the nuclei. In ultra-peripheral collisions (UPCs), characterized by a large impact parameter between the nuclei, the outgoing particles exhibit back-to-back production in the transverse plane, which provides precise and efficient identification. This talk...
We present a framework to study (cross-)cumulants and balance functions of identified hadrons in heavy-ion and hadronic collisions using two-point correlation function with local charge conservation. We discuss the effects of multiple conserved charges (in particular strangeness), as well as correlations due to hadronic interactions, resonance decays, baryon annihilation, and light nuclei...
By combining femtoscopic interferometry with an optical deblurring algorithm, we present a novel method to image the source in heavy-ion collisions while simultaneously extracting the interaction strength between particle pairs. We apply this method to the published STAR data on Au+Au collisions at $\sqrt{s_{\rm NN}}=200$ GeV, obtaining new fits for both the spatial distribution of the...
Recent measurements of the charm baryon-to-meson ratios in pp collisions show an enhancement with respect to the measurement in $e^+e^-$ collisions indicating that coalescence could be a charm-quark hadronization mechanism at play in pp collisions in addition to charm-quark fragmentation. We further investigate charm-quark hadronization by studying the production of $\Xi_c^0\rightarrow...
In ultrarelativistic heavy-ion collisions, the Quark–Gluon Plasma (QGP) is formed, and the study of anisotropic flow serves as a key tool to probe its properties in detail. While the flow of light and strange hadrons reflects the collectivity developed during the partonic stage, resonance particles can experience additional effects during the hadronic phase due to interactions of their decay...
Observations in small collision systems have revealed features reminiscent of collective behavior, traditionally associated with the formation of quark–gluon plasma in heavy-ion collisions. Whether such effects arise from genuine collective dynamics or from the interplay of softer and harder components of particle production remains an open question. The underlying event (UE), the softer...
Understanding the transition from baryon stopping to transparency provides crucial insights into QCD matter properties at finite baryon density - a key goal of the RHIC Beam Energy Scan program. We present a generalized and improved multi-fluid dynamic approach to model heavy-ion collisions at RHIC Beam Energy Scan energies. The extensions touch two key aspects of the modelling.
The first...
We develop the eigen-microstate framework as a new approach to identify criticality in relativistic heavy-ion collisions. We construct the original microstate, defined as the final-state particle fluctuations of a single event. By examining ensembles of such original microstates with and without critical signals, we demonstrate that the corresponding eigen-microstate can extract and reveal the...
Short-lived resonances are powerful probes to study the hadronic phase in high-energy collisions, as their lifetimes are comparable to the duration of the hadronic stage. Their yields and spectral properties are affected by the interplay between rescattering and regeneration processes in the hadronic phase. Among them, the $\text{f}_0(980)$ resonance, with a lifetime of about 3–5 fm/c as...
The observation of collective flow phenomena in small collision systems challenges our understanding of quark-gluon plasma (QGP) formation and evolution. This complexity lies in the initial geometries, which are influenced by both nucleon configuration and subnucleonic fluctuations, introducing uncertainties in interpreting flow patterns. We disentangle these contributions through comparative...
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)....
We find that chiral mean-field models can produce a phase diagram with 3 critical points: the usual liquid-gas transition, deconfinement, and also a new critical point that arises from a transition from the baryon octet phase into a phase dominated by strange and resonance baryons. At the onset of this phase we find a drastic increase in strangeness since cascade baryons tend to dominate. We...
Open heavy-flavor production studies at LHCb provide precise probes of
hadronization in collision systems ranging from $\gamma$Pb interactions to semi-central PbPb collisions. Studies of heavy baryons and mesons containing two different heavy or strange valence quarks probe the interplay of statistical hadronization, coalescence, and multi-parton interactions. From another point of view, the...
Collective behaviors in pp and p–Pb collisions have sparked debate on the onset of hydrodynamics in small systems. However, the proton's poorly constrained geometry has hindered definitive conclusions. The 2025 LHC runs with OO and Ne–Ne collisions provide a unique solution: their well-defined initial states allow a direct test of whether collectivity stems from hydrodynamic flow or...
Charm and beauty quarks are produced at the earliest stages of ultrarelativistic heavy-ion collisions through hard scattering processes. Quarkonium production serves as a probe of the perturbative aspects of quantum chromodynamics (QCD) through heavy-quark production in the initial hard scattering, while the non-perturbative aspects play a crucial role in the subsequent formation of the heavy...
This presentation reports new ATLAS measurements of soft-particle production and collective flow in light-ion collisions at the LHC. Charged-particle pseudorapidity densities ($dn/d\eta$) and average transverse momenta ($\langle p_T\rangle$) are measured in O+O and Ne+Ne collisions at $\sqrt{s_{NN}} = 5.36$ TeV over the fiducial range $|\eta| < 2.5$ and $0.27 < p_T < 5$ GeV. Fits to the...
We discuss charm-strange mesons, Ds, Ds, Ds0(2317), Ds1(2460), and X(3915) mesons produced from charm and strange quarks in the quark-gluon plasma in heavy-ion collisions at \sqrt{s_{NN}}=5.02 TeV. We first investigate the transverse momentum distribution of charm and strange quarks at \sqrt{s_{NN}}=5.02 TeV in the quark-gluon plasma based on transverse momentum distributions of \phi and D^0...
High-energy heavy-ion collisions create a quark–gluon plasma (QGP) with approximately restored chiral symmetry. Lattice QCD determines the chiral crossover temperature to be $T_c = (156.5 \pm 1.5) \, \mathrm{MeV}$, below which chiral symmetry is spontaneously broken and pions emerge as pseudo–Goldstone bosons. Yet, this chiral transition—second order in the chiral limit—is absent from current...
Accurate modeling of the space–time evolution of the quark–gluon plasma (QGP) through relativistic hydrodynamics is essential for connecting initial-state fluctuations to final-state observables and for understanding interactions between hard probes and the evolving QGP in heavy-ion collisions. However, full hydrodynamic simulations are computationally intensive, posing major challenges for...
The hadronisation of charm quarks within the strangeness-rich environment of the Quark-Gluon Plasma (QGP) offers a unique laboratory for studying non-perturbative QCD dynamics. We present new measurements from the CMS experiment utilising the high-statistics lead-lead (PbPb) collision datasets from Run 2 and Run 3. This work features a high-precision measurement of the elliptic ($v_2$) and...
Understanding the interaction of strange baryons with nucleons is a key ingredient for describing dense baryonic matter, where the appearance of hyperons in the cores of neutron stars is expected to strongly soften the equation of state, hence limiting the maximum stellar mass. New constraints, not only on two-body but also on multi-body hyperonic interactions, are necessary to address this...
Heavy quarks are produced predominantly in the initial hard scatterings of high-energy hadronic collisions and therefore provide sensitive probes of heavy-flavor production mechanisms and hadronization in small collision systems. Recent measurements at RHIC and the LHC have shown a strong correlation between heavy-flavor yields and event charged-particle multiplicity in p+p and p+A collisions,...
We use the Einstein-Maxwell-Dilaton model, which is based on the gravity/gauge duality framework, supplemented by Bayesian inference to calculate key transport coefficients and energy loss of the quark-gluon plasma including baryon conductivity, baryon diffusion, bulk viscosity, shear viscosity, drag force, heavy quark diffusion coefficient and jet quenching parameter. Our model is calibrated...
Quarkonium production in hadronic collisions is a key observable for studying the interaction of heavy quarks with the nuclear medium. While quarkonium states can dissociate and recombine in nucleus-nucleus collisions, their production in smaller systems may be influenced by a combination of initial- and final-state effects such as shadowing and co-mover breakup. Thanks to excellent vertexing...
The baryon number transport from beam rapidity to mid-rapidity has been observed from the detection of an excess of hyperons over anti-hyperons numbers around mid-rapidity in nuclear collisions at RHIC energies. To understand the dynamics of the baryon number transport over a large rapidity gap, the gluon junction model, which suggest the Y-shaped gluonic junction in proton and neutron may...
Understanding charm-quark hadronization is key to characterizing the quark–gluon plasma formed in heavy-ion collisions. Measurements of strange and non-strange charm hadrons across collision systems probe hadronization mechanisms, particularly in Pb–Pb collisions where abundant strangeness is expected to enhance recombination effects and provide stringent tests of statistical-hadronization...
Fluctuations and correlations of conserved charges, such as net-charge (Q), net-baryon (B), and net-strangeness (S), are sensitive to the quantum chromodynamics (QCD) phase transition and the QCD critical point. To achieve this goal, previous studies have focused on the fluctuations of conserved charges, while the correlations of conserved charges also hold significant physical significance....
We present a novel Monte-Carlo implementation of the EKRT model, MC-EKRT, for computing partonic initial states in high-energy nuclear collisions [1]. Our new MC-EKRT event generator is based on collinearly factorized, dynamically fluctuating pQCD minijet production, supplemented with a saturation conjecture that controls the low-$p_T$ particle production. Previously, the EKRT model has been...
The production of heavy quarkonium — bound states of a heavy quark (charm or beauty) and its corresponding antiquark — is widely used to probe both the properties of quantum chromodynamics (QCD) in high-energy proton–proton (pp) collisions and deconfinement in heavy-ion collisions. In pp collisions, precise measurements of quarkonium production cross sections, polarization, and correlations...
sPHENIX is a next-generation experiment at RHIC for jet and heavy-flavor physics which was fully commissioned in 2024. Using its novel streaming-readout-capable, precision tracking system, sPHENIX collected 100 billion unbiased p+p collisions, and a further sample of minimum-bias Au-Au collisions, in Run-24. A key measurement of the sPHENIX heavy flavor physics program are measurements of the...
One of the most unanticipated findings of the LHC heavy ion program is the observation of stronger suppressions of the excited $\Upsilon$ states compared to the lower $\Upsilon\mathrm{(1S)}$~state in \mbox{proton-lead} collisions, with the same hierarchy as seen in the larger \mbox{lead-lead}~(PbPb) collision events. Together with other observations of signatures of quark-gluon plasma...
Authors: Y. Zhou, J. Aichelin, C. Blume, E. Bratkovskaya, G. Coci, N. Herrmann, S. Gläßel, V. Kireyeu, Y. Leung, V. Voronyuk, I. Vassiliev, M. Winn, N. Xu, J. Zhao
The equation-of-state (EoS) at high baryon density is crucial for understanding the behavior of nuclear matter under extreme conditions. The directed flow of protons and $\Lambda$ baryons has long been recognized as a sensitive...
Heavy-flavour production represents a crucial probe for studying transport properties of the Quark-Gluon Plasma (QGP), with the spatial diffusion coefficient $D_s(T)$ encoding the interaction strength between heavy quarks (HQs) and the medium. Recent lattice QCD (lQCD) results with dynamical fermions show very low values, $2\pi T D_s \approx 1$ for charm quarks at $T = T_c$, much lower than...
ALICE will commission the Inner Tracking System 3 (ITS3), replacing the three innermost layers of the existing vertex spectrometer during the Long Shutdown 3 (2026-30) of the LHC at CERN. It will consist of six truly cylindrical, bent, wafer-scale monolithic active pixel sensors based on the TPSCo 65 nm technology. ITS3 will have a low material budget (0.09% X0 per layer) and the innermost...
The suppression of quarkonium production in heavy-ion collisions has long been recognized as a key signature of QGP formation, reflecting the medium’s temperature and color-screening properties. However, interpreting the observed nuclear modification factor ($R_{AA}$) remains challenging due to the interplay between hot-medium effects (dissociation and regeneration) and cold nuclear matter...
Quarkonia are key probes of the quark-gluon plasma (QGP). Their azimuthal anisotropies, quantified by flow coefficients, provide insight into the collective behavior and degree of thermalization of heavy quarks in the medium. In particular, the elliptic flow $v_2$ of the J/$\psi$ meson in Pb-Pb collisions at the LHC has revealed significant collectivity, supporting scenarios of charm-quark...
The Compressed Baryonic Matter (CBM) experiment is currently being constructed at the Facility for Antiproton and Ion Research (FAIR). It is designed as a fixed target experiment to explore the QCD phase diagram in the baryon rich domain in nucleus-nucleus collisions at an unprecedented interaction rate of up to 10 MHz. This will allow the study of extremely rare probes with high precision...
Forty years ago, Witten suggested that dark matter might consist of macroscopic droplets of strange quark matter, formed during a cosmological first-order phase transition. Although lattice QCD at small baryon chemical potential points to a smooth crossover, scenarios in which the early Universe still encounters first-order dynamics remain plausible. We revisit the conditions under which...
The properties of dense astrophysical objects, such as neutron stars, are governed by the equation of state of nuclear matter. At the extreme baryon densities reached in their cores, hyperons are expected to appear as energetically favorable degrees of freedom. Constraining hyperon–nucleon interactions is therefore essential for accurate astrophysical modeling. However, in the case of the...
The charm quark serves as a powerful probe for investigating the properties of the hot and dense QCD medium, the quark-gluon plasma (QGP), created in high-energy heavy-ion collisions. Building on previous studies that demonstrated the applicability of a fluid-dynamic description of charm quarks in the quark-gluon plasma, the present work (https://arxiv.org/abs/2510.25601) extends this...
NA60+/DiCE is a new experiment, proposed for data taking in the coming years, which aims to explore the high baryochemical potential region of the QCD phase diagram. NA60+/DiCE will perform a beam-energy scan with Pb–Pb and p–A collisions in the range 6 < \sqrt{s_{NN}} < 17, taking advantage of the high-intensity beams available at the CERN SPS.
The experimental apparatus comprises a vertex...
Final-state effects such as interactions with co-moving particles or quark coalescence can influence the hadronization dynamics of heavy quarks in nuclear collisions. To investigate these phenomena, we present new multi-differential measurements of the $\Upsilon(nS)/\Upsilon(1S)$ production ratios as functions of rapidity, transverse momentum, and charged-particle multiplicity in proton-lead...
Quarkonium states, and in particular charmonium, have been recognized
as sensitive probes of the properties of hot and dense strongly
interacting matter created in relativistic heavy-ion collisions. Since
the pioneering work of Matsui and Satz, who proposed that the
suppression of the $J/\psi$ meson could signal the onset of quark–gluon
plasma (QGP) formation, numerous theoretical...
We compute the full cosmic trajectories of the early Universe across the QCD phase diagram as the plasma cools from $T\simeq500\,$MeV to $30\,$MeV, assuming $\beta$-equilibrated matter.
The trajectories are obtained by simultaneously solving baryon-number, electric-charge, and lepton-asymmetry conservation, closed by a state-of-the-art lattice-QCD equation of state: a fourth-order Taylor...
Recent results from the LHC on oxygen–oxygen (O-O) and xenon–xenon (Xe-Xe) collisions open a new window for investigating the interplay of cold nuclear matter (CNM) and quark–gluon plasma (QGP) effects in small collision systems. Building upon recent theoretical work on particle production dynamics in heavy ion reactions, we present an updated study of light and heavy hadron modification...
Quarkonium production has long been considered as one of the golden probes to study the quark-gluon plasma (QGP). In fact, the early production of heavy quarks ($c\bar{c}$ and $b\bar{b}$) makes quarkonia an ideal tool to investigate the evolution of the hot and dense medium produced in ultra-relativistic heavy-ion collisions. Moreover, at LHC energies the recombination of uncorrelated charm...
The ALICE Collaboration has proposed a completely new apparatus, ALICE 3, for the LHC Run 5 (LoI, arXiv:2211.02491). The detector consists of a large pixel-based tracking system covering eight units of pseudorapidity, complemented by multiple systems for particle identification, including silicon time-of-flight layers, a ring-imaging Cherenkov detector, a muon identification system, and...
Connecting neutron stars to heavy-ion collisions is essential for constraining the neutron star Equation of State and its interior structure. One such phenomenological tool is the symmetry energy expansion, which characterizes the energy difference between symmetric nuclear matter and pure neutron matter [1]. However, the usual expansion is ill-defined when strangeness is present [2]. We...
In ultra-peripheral collisions (UPCs), photon-induced production mechanisms include resonant vector-meson photoproduction, the non-resonant Drell-Soding process, and $\gamma \gamma$ processes. Coherent vector meson photoproduction provides a sensitive probe of the gluonic structure of heavy nuclei; vector mesons of different mass (e.g. $\phi$ and J/$\Psi$) offer insights into different...
Energetic collisions of heavy nuclei have long been known to create a hot and dense state of matter known as the quark-gluon plasma (QGP). The QGP may also be created in collisions of heavy-on-light and even light-on-light nuclear collisions. One key signature of QGP formation is the development of long-range angular correlations, which indicate the propagation of early-time position-space...
