The study of strangeness production in small collision systems provides crucial insights into the mechanisms governing particle production at the LHC. Recent observations in protonโproton (pp) and protonโlead (pโPb) 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 coreโcorona 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 protonโproton...
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 charmโanticharm 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 spinโorbit 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, NeโNe, 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 ฮ hyperons in heavy-ion collisions at โsโโ = 200 GeV. Our findings reveal a pronounced sensitivity to the choice of initial-state modeling and the viscous properties of the quarkโgluon 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 PbโPb 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 spaceโtime 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 OโO and NeโNe collisions at 5.36 TeV and 200 GeVโ 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, protonโnucleus measurements further probe the...
In the KaluzaโKlein 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 quarkโgluon 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 $\bar{\Xi}$ ฬ 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 protonโproton collisions at โs = 200 GeV in 2024. In this poster, we present the current status of two-particle correlation analyses in protonโproton 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 quarkโgluon plasma (QGP). The transverse momentumโdependent isotropic flow observable, $v_{0}(p_{T})$, probes radial flow fluctuations and their evolution from small to large systems, providing sensitivity to the mediumโs 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$_T$/dฮท) 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 hyperonโnucleon interaction โ 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 numberโ 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 โQuantum 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 protonโproton (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 protonโproton collisions at $\sqrt{s} = 510~\mathrm{GeV}$ recorded...
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,...
Using the finite-temperature Chiral Mean Field (CMF) model within the MUSES frameworkโwhere the baryon octet and decuplet, including strange baryons, interact via meson fields and are treated at finite ๐ through Fermi integralsโwe 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 โ including light and charmed species โ 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 โ the formation of โดHe nuclei within larger nuclei โ 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 ฮณฮณ 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 QuarkโGluon 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 quarkโgluon 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 3โ5 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...
