The relativistic hydrodynamic model has been vital to the analysis of the QCD matter created in high-energy heavy-ion collisions. Experimental data indicate that low momentum particles are thermal and hydrodynamic, while high momentum particles are non-thermal and perturbative. We investigate two scenarios - (i) the Tsallis hydrodynamic model where an extended momentum range is treated as...
The collective observables play critical roles in probing the properties of quark-gluon-plasma created in relativistic heavy-ion collisions, in which the information on initial collision geometry is crucial. However, the initial collision geometry, e.g., the reaction plane, cannot be directly extracted in the experiment. In this talk, we demonstrate the idea of determining the reaction plane...
The electron scattering process has been used to determine the nuclear charge radius. Similarly, the photon scattering process can be used to determine the nuclear strong-interaction radius, primarily through the diffractive photoproduction of vector mesons. Such an approach has been proven effective at RHIC. The isobar collisions of Ru+Ru and Zr+Zr at RHIC provided an excellent opportunity...
We propose a novel effect that accounts for the photon emission from a quark-gluon plasma in the presence of a weak external magnetic field. Although the weak magnetic photon emission from quark-gluon plasma only leads to a small correction to the photon production rate, the induced photon spectrum can be highly azimuthally anisotropic, as a consequence of the coupled effect of the magnetic...
Dielectron production is a powerful tool to investigate the properties of the quark-gluon plasma created in relativistic heavy-ion collisions, as they carry information about the temperature of the medium and its space-time evolution without any distortion due to final-state interactions. If a medium is created in such small colliding systems, it should give rise to an additional contribution...
We propose a relativistic theory for spin density matrices of vector mesons based on Kadanoff-Baym equations in the closed-time-path formalism. The theory puts the calculation of spin observables such as the spin density matrix element $\rho_{00}$ for vector mesons on a solid ground. Within the theory we formulate $\rho_{00}$ for $\phi$ mesons into a factorization form in separation of...
We study the two-point functions from chiral kinetic theory which characterize the response to perturbative vector and axial gauge fields in magnetized chiral plasma. In the lowest Landau level approximation, the solution of chiral kinetic equations gives density waves of electric and axial charges, which contain chiral magnetic wave implied by the axial anomaly and magnetic field. We then...
Relativistic heavy ion collisions, especially the recent isobar ($^{96}_{44}$Ru+$^{96}_{44}$Ru and $^{96}_{40}$Zr+$^{96}_{40}$Zr) collisions, provide an opportunity to determine the structures of the colliding nuclei with good precision. Nuclear deformation, triaxiality, and sub-nucleon structure have recently been studied by $v_{n}-p_{T}$ correlations; size and shape differences between Ru...
Abstract: Jet energy loss and transverse momentum broadening can be implicitly represented by jet transport coefficient $\hat{q}$ distributed in the whole phase space of the QGP medium. The gradient of $\hat{q}$ perpendicular to the momentum direction of an energetic parton leads to an asymmetry of the transverse momentum distribution, which can be used for the initial jet production...
Event-by-event fluctuations of mean transverse momentum, $\langle p_{\rm{T}}\rangle$, help to characterize the properties of the bulk of the system created in ultrarelativistic heavy-ion collisions, called the quark-gluon plasma (QGP). The fluctuations are closely related to the dynamics of the phase transition from the QGP to a hadron gas.
In this contribution, event-by-event fluctuations...
Mach cones are expected to form in the expanding quark-gluon plasma (QGP) when energetic quarks and gluons (called jets) traverse the hot medium at a velocity faster than the speed of sound in high-energy heavy-ion collisions. The shape of the Mach cone and the associated diffusion wake are sensitive to the initial jet production location and the jet propagation direction relative to the...
We calculate the yields of molecular configuration hadrons produced by heavy ion collision using coalescence model. First, we calculated the transverse momentum distribution of deuteron using the coalescence model from proton transverse momentum distribution in Pb-Pb collisions at 2.76TeV measured by ALICE collaboration. From this, we estimate the parameters required for coalescence model at...
The QCD phase transition signals at RHIC are expected to be observed via the measurement of net-proton's high order cumulants [1]. In this talk, we will present our recent study of dynamical effects on the high order cumulants of the QCD chiral field in a system with finite-size. We find much stronger memory effects on the first-order phase transition side than on the crossover side. Besides,...
There is presently no consensus on how the $\phi$ meson mass and width will
change once it is put in a dense environment such as nuclear matter.
While many theoretical works exist, connecting them with experimental
measurements remains non-trivial task, as the $\phi$ meson in nuclear matter is
usually produced in relatively high-energy pA reactions, which are generally...
The sPHENIX experiment at Brookhaven National Laboratory (BNL) is a next-generation experiment equipped with a large solid angle detector to detect jets and precisely measure QGP properties. sPHENIX's INTT detector is a strip-type silicon detector that is positioned 7~10 cm from the collision point. The signal transmission cable of the INTT detector requires the development of a conversion...
J-PARC is one of the world’s highest-intensity proton accelerators for material and life sciences, neutrino physics, and hadron and nuclear physics in the GeV energy region. We are planning to accelerate world's high-intensity heavy-ion beams at J-PARC. We will build a new compact heavy-ion linac and a booster ring as an injector, while we utilize the existing RCS and MR synchrotrons to...
It is widely believed that gauge theories with fundamental matters exhibit a smooth connection between the confining and Higgs regimes. This Higgs-confinement continuity is of crucial importance to the quark-hadron continuity conjecture, which claims a smooth crossover between the nuclear superfluidity and color superconducting phases in dense QCD. Certain gauge theories with superfluidity,...
Hanbury Brown and Twiss (HBT) interferometry is used to investigate the shape and size of the matter produced in high-energy nuclear collisions. The Koonin-Pratt equation, which represents convolutions of the source function and the two-particle wave function in vacuum, has been used for the analysis. However, particles produced in a medium are affected during passing through it. In this talk,...
The Schwinger model (QED in one spatial dimension) is known as a toy model of QCD. We perform a Monte Carlo study of the Schwinger model at finite density. We circumvent the notorious sign problem by using the bosonization technique. We find that the number density is a smooth function of the chemical potential. This talk is based on arXiv:2303.05481 [hep-lat].
Recent measurements of the baryon-to-meson production yield ratios between charm baryons ($\Lambda_\mathrm{c}^{+}$, $\Sigma_\mathrm{c}^{0,++}$, $\Xi_\mathrm{c}^{0,+}$, $\Omega_\mathrm{c}^{0}$) and $\mathrm{D}$ mesons ($\mathrm{D}^0$) in small collision systems show a significant enhancement with respect to the measurements performed in $e^{+}e^{-}$ collisions. These results were compared with...
Quark-gluon plasma is a substance that scientists predict existed in the early universe according to Quantum Chromodynamics, and evidence for its existence is being discovered through both theory and experiment. Since QGP is in thermal equilibrium, researchers are studying its thermal properties to understand how it evolves over time. As the temperature rises, mesons separate into quarks and...
The studies of multi-strangeness hypernuclei help us further understand the interaction between hyperons and nucleons. This work discusses the productions of triple-baryons including $\Omega$, namely $\Omega NN$ and $\Omega\Omega N$, their decay channels and the baryon number dependence of productions. A variation method is used in calculations of bound states and binding energy of $\Omega NN$...
EIC stands for Electron-Ion Collider, a circular accelerator to be constructed at BNL, which is expected to discover new physics, such as those related to gluon condensation, by colliding electrons and nuclei.
In Japan, the EIC Japan group has been established and is active.
The Japan group has decided to proceed with the development of barrel TOF and is planning to use AC-LGAD in its...
During the Long Shutdown 3 (2026-2028) at LHC, ALICE is planning to replace the innermost three layers of the existing inner tracking system (ITS2) with a new silicon detector (ITS3) which is under development. ITS3 is based on truly cylindrical half barrels using wafer-scale monolithic active pixel sensors reducing the material budget and significantly. Thus, ITS3 will improve the trajectory...
The ALICE Collaboration is planning to install a new forward calorimeter (FoCal) as a detector upgrade to the ALICE experiment at LHC during the next long shutdown from 2027 to 2029. FoCal consists of the Si+W electromagnetic and conventional sampling hadronic subsystems (FoCal-E and FoCal-H, respectively), and it will cover the pseudorapidity interval of 3.4 < η < 5.8 at a place of 7 meters...
In non-central high-energy nuclear collision, very strong magnetic field is produced. High intensity magnetic field have never been directly detected experimentally, and we propose to measure virtual photon polarization as direct evidence. Since anisotropy appears in the lepton pair decay plane of a virtual photon polarized by a magnetic field, we aim to detect virtual photon polarization by...
The motivation of geometry engineering with p, d, and 3He projectiles at RHIC is to investigate the relation between initial geometry and final momentum anisotropy, which is thought to be strong evidence of QGP. PHENIX results show the elliptic and triangular flow hierarchy in p/d/3He+Au collisions follows the eccentricity described by the MC Glauber model. However, the initial geometry of...
We employ the AdS/CFT correspondence to study the jet quenching effect in Quark-gluon plasma in heavy-ion collisions.The nuclear modification factor $R_{AA}$ and elliptic flow parameter $v_{2}$ are studied in different-centrality collisions at RHIC and LHC.Our numerical results agree with data.Magnetic field and chemical potential of the medium are also considered for the observable...
In this study, we present the model study of the charged-particle multiplicity density, dNch/dη in Pb-Pb collisions at a centre-of-mass energy per nucleon-nucleon pair of $\sqrt{s_\mathrm{NN}}$ = 5.36 TeV. The centre-of-mass energy for Pb-Pb collisions is the highest ever that is planned to be collected by LHC at the end of 2022 for the first time. The multiplicity of charged particles...
We show that the topological charge of nonabelian gauge theory is not observable. We then inspect the phenomenological consequences to hadron physics and experiments such as the physical relevance of the axial U(1) symmetry and the unobservability of the chiral magnetic effect.
In relativistic heavy-ion collisions, a hot and dense medium called QGP is created. Intriguingly, the collective motion of produced particles, which is thought to be evidence of the formation of strongly interacting QGP, has also been observed in high-multiplicity events of small systems like $pp$ and $p$--Pb collisions. In addition, studying the flow of identified particles with different...
A new detector was installed in ALICE in the forward region during LHC LS2 with the aim to improve the accuracy of the dimuon opening angle measurement more than ever since the LHC Run 3. Such new detector cannot identify muons and measure their momentum, so it must be used in combination with an existing detector. Therefore, it is necessary to correctly match the tracks reconstructed by...
Fluctuations of harmonic flow along pseudorapidity $\eta$, known as flow decorrelations, is an important probe of the initial condition and final state evolution of the quark-gluon plasma. We show that the flow decorrelations are sensitive to the deformations of the colliding nuclei. This sensitivity is revealed clearly by comparing flow decorrelations between collisions of isobars,...
The fragmentation of partons is studied using the jet fragmentation transverse momentum, j_{T}. The j_{T} is defined as the perpendicular component of the momentum of the constituent particle with respect to reconstructed jet momentum, \vec{p}_{jet}. The jT provides a measurement of the transverse momentum spread of the jet fragments. Recently, the direct dead-cone effect was measured by ALICE...
ALICE3, the next-generation heavy-ion experiment, has been proposed for the LHC RUN 5 and 6 to investigate the Quark Gluon Plasma properties, exploiting precise measurements of heavy-flavour probes as well as electromagnetic radiation. These measurements require excellent particle identification (PID) capabilities in a wide transverse momentum range.
The development of a Ring Imaging...
Vorticities in heavy-ion collisions (HIC) are supposed to induce spin alignment and polarization phenomena of quarks and mesons. In this paper, we consider a uniformly rotating medium in which quark and anti-quark pairing are suppressed. Consequently, in the framework of Nambu-Jona-Lasinio (NJL) model, dynamical quark masses are descending as the angular velocities grow. In case of vector...
Jets provide unique and powerful probes to study Quantum Chromodynamics in proton-proton collisions and the quark-gluon plasma medium in heavy-ion collisions. Among these probes, measurement of jet substructure and of the distribution of hadronic constituents within a jet provide a detailed look into the partonic shower process. ALICE has recently measured and published transverse momentum...
High-energy partons generated in relativistic particle collisions create well-collimated showers of particles, which are called jets. The jet study is used widely in heavy-ion collisions, where the quark-gluon plasma (QGP) medium forms. Previous studies from RHIC and LHC indicate that dijet invariant mass can be sensitive to modifications caused by the QGP medium. In this study, we present a...
Experimentally observed splitting of directed flow ($v_1$) between proton and anti-proton has been a challenging observable for the models to describe. We propose a two-component baryon deposition scheme driven by participants as well as binary collision sources. Evolving such a profile through a hybrid framework (hydrodynamics + hadronic transport), we are able to capture the $v_1$ of light...
The short-lived resonances are sensitive probes of the hadronic phase whose lifetime is several fm/$c$ in heavy-ion collisions. The final state yields are expected to be affected by re-scattering and regeneration after chemical freeze-out. The measured yield of resonances tends to be suppressed by the re-scattering of daughter particles with other hadrons. On the other hand, it tends to be...
We are developing a Forward Calorimeter (FoCal) as one of the proposed ALICE upgrade projects at CERN. The FoCal extends the scope of ALICE, which was designed for the comprehensive study of hot and dense partonic matter, by adding new capabilities to explore the small-x region in parton distribution for nucleons and nuclei.
The electromagnetic calorimeter (FoCal-E) equipped with 18 pad...
Using a (3+1)-D hybrid framework with parametric initial conditions, we study $v_1(y)$ of identified particles, including pions, kaons, protons, and lambdas, in Au+Au collisions performed at $\sqrt{s}$ ranging from 7.7 to 200 GeV. The dynamics in the beam direction is constrained using the measured pseudo-rapidity distribution of charged particles and the net proton rapidity distribution....
The Ridge behavior in high-multiplicity pp collisions has been discussed a lot since it was first reported in year. Because small systems cannot provide sufficient conditions to produce a medium called QGP, in which the ridge behavior is understood with hydrodynamics. In this work, we propose the pure kinematic mechanism between jets and medium partons as tools for describing the Ridge...
Since phenomena induced by the hydrodynamic fluctuations include the information of transport coefficients, the study of fluctuations could open up a new way of diagnosing the QGP precisely. We derive equations of motion (EoM) of hydrodynamic fluctuations by considering the perturbative expansion of energy-momentum tensor around the Bjorken's boost invariant solution. These EoMs are derived...
Relativistic hydrodynamics has been successful in describing space-time evolution of matter created in high-energy nuclear collisions. One conventionally assumes that created matter becomes fluids all at once at a certain initial time. It is, however, not at all trivial from which stage after the collision the fluid picture can be applied. Whether non-linear hydrodynamic equations obey the...
In April of this year, the sPHENIX experiment began at Brookhaven National Laboratory (BNL) in the United States, measuring the properties of a quark-gluon plasma (QGP) state created by colliding gold atoms accelerated by the Relativistic Heavy Ion Collider (RHIC). The sPHENIX Japan group (Nara Women's University, Rikkyo University, and RIKEN) is responsible for developing and constructing the...
Measurements of weak bosons, W$^{\pm}$ and Z$^{0}$, are powerful tools to study quantum chromodynamics (QCD). Due to their large masses, they are predominantly produced via quark-antiquark annihilation in the early stage of pp and heavy-ion collisions. Therefore, their production can be described by the perturbative QCD (pQCD) and is sensitive to the parton distribution function in nucleon and...
We carry out the first theoretical investigation on yields and the hardest parton splitting of large-radius jets reclustered from small radius ($R=0.2$) anti-$k_t$ jets in Pb+Pb collisions, and confront them with the recent ATLAS measurements.
The Linear Boltzmann Transport (LBT) model is employed for jet propagation and jet-induced medium excitation in the hot-dense medium. We demonstrate...
The production of quarkonia in high-energy heavy-ion collisions has been studied extensively to understand their production mechanisms and properties of QGP. Recent PHENIX studies show that the increasing J/ψ yields versus multiplicity in p+p collisions are similar to results in different J/ψ acceptance and collision energy, implying that MPI contributes to J/ψ production at RHIC energy. The...
Neuron, the basic unit of nerve cells, transmits stimuli by sending neurotransmitters to other neurons when receiving signals above the threshold. The algebraic structure that mimics this process is called perceptron, the basic unit of the artificial neural network (ANN). The ANN is used to solve problems in many fields of data processing such as classification, and is a useful tool,...
The origin of hadron masses cannot be attributed to the Higgs mechanism alone. On top of that, spontaneous breaking of chiral symmetry, potentially restored at extremely high temperatures, should play an important role. Light vector mesons (ρ, ω, φ) are highly sensitive to chiral symmetry restoration, so that a modification in their mass is expected. This study evaluates the detectability of ω...
We investigate the flavor dependent jet quenching, by performing a systematic analysis of medium modifications of the inclusive jet, $\gamma$-jet, and $b$-jet in Pb+Pb collisions relative to those in pp at the LHC. Our results from MadGraph+PYTHIA and LBT well describe the experimental data of the inclusive jet, $\gamma$-jet and $b$-jet both in pp and AA collisions simultaneously. We then use...
Recently, experimental measurements of the energy-momentum tensor (EMT) distribution inside hadrons receive attentions their theoretical investigations are becoming increasingly important. In this presentation, focusing on localized structures in quantum field theory, we calculate the one-loop correction to the distribution of EMT around a kink in 1 + 1 dimensional $\phi^4$ model and...
The precise knowledge of hyperon-hyperon interaction is one of the key measurements in QCD. To achieve this goal, it is fundamental to identify hyperons with a high purity in a high charged-particle multiplicity environment, such as a central Pb-Pb collisions. Thanks to its excellent particle identification and tracking performance, the ALICE experiment at the LHC is ideal for these...
The quark-gluon plasma(QGP) is considered the state of the early universe. The azimuthal anisotropy for charmonium states has been researched as one of the probes to understand the nature of the QGP. In this presentation, we will report recent progress regarding the study of the elliptic and triangular flow for prompt and nonprompt $\rm{J}/\psi$ and prompt $\psi$(2S) states in lead-lead...
The upgrades for Run 3 of the CMS experiment at LHC improves both hardware and software, resulting in the enhancement of detection efficiency and data streaming capabilities for the accumulation of the physics data. In this poster, we will introduce the latest strategy of the muon trigger for the Run3 heavy-ion experiment. It employs the newly developed algorithms to increase the trigger...
FAZIA (Forward A and Z Identification Array) is designed to identify charges and masses of reaction products from heavy-ion collisions from a few tens of MeV to about a hundred MeV per nucleon.
One basic unit of FAZIA consists of 4 x 4 shaped, three-layered telescopes.
The first and second layers are silicon sensors with different thicknesses of 300 um and 500 um, respectively, and one CsI...
Heavy quarks, produced in hard-scattering processes in the very early stage of heavy-ion collisions, are efficient probes of the quark-gluon plasma (QGP) properties through its full evolution. They subsequently decay into particles such as muons and electrons. In ALICE, at LHC energies, muons are detected by the forward muon spectrometer and the Muon Forward Tracker (MFT). Full simulations...
The thermalization and chemical equilibration processes of the gluon dominated matter produced immediately after high energy collision are still poorly understood due to its far-from equilibrium nature. We use transport simulation to explore this phase where we include 2-to-3 interactions which are important to the thermal and chemical equilibration processes as the source of particle and...
At sufficiently high temperatures and pressure, Quantum Chromodynamics predicts that ordinary nuclear matter undergoes a phase transition. This new state of matter is called Quark Gluon Plasma (QGP) and is characterized by deconfined quarks and gluons. In this context, high energy heavy ion collions have been historically used to recreate the QGP in the laboratory. In recent years, at the...
In this work, we explore the impact of expansion of medium on angular distribution of gluons at different kinematical scales in a medium-induced cascade. Firstly, we study the scaling of the gluon spectra at low−$x$ between expanding and static media and numerically obtain transverse momentum broadened spectra. Next, we study angular distributions for the in-cone radiation for different media...
Previously, the ridge phenomenon in heavy-ion collisions such as PbPb has been well described by hydrodynamic models. However, the ridge structure of a small system, such as pp collisions, which could not offer enough conditions to create the medium required by hydrodynamic models, was observed in high-multiplicity events. This is why we focus on the Momentum Kick Model (MKM), which explains...
We investigate how the event-by-event fluctuations of the final-state distribution function of nucleons physically affect the yield ratio of light nuclei based on the coalescence model.
The yield ratio of light nuclei, $N_tN_p/N_d^2$ (with $N_t$, $N_p$, and $N_d$ being triton, proton, and deuteron numbers, respectively) [1], is one of the observables suggested for a possible signal of the...
We present a study of the nuclear-medium induced transverse momentum broadening of particle production in future electron-ion-collision (EIC) experiments. By considering the multiple scattering between hard partons and cold nuclear medium within the higher-twist factorization framework in perturbative QCD, we calculate the transverse momentum broadening of single hadron production in...
Using the string melting version of a multi-phase transport (AMPT) model without or with the sub-nucleon geometry for the proton to study multiparticle cumulants in p+p collisions at 13 TeV [1]. We have found that both versions of the model can produce c2{4}<0 for high-multiplicity events, which is thought to be the signal of the collective flow. The relation between c2{4} and the parton...
We study the zero-temperature and finite-density phase of QCD in 1+1 dimensions on the basis of Hamiltonian lattice QCD and matrix product states. We variationally approximate the wave function of the ground state with nonzero chemical potential using the density matrix renormalization group and compute physical observables such as equation of state, chiral condensate, and quark distribution...
Hadronic resonances are effective tools for studying the hadronic phase in ultrarelativistic heavy-ion collisions. In fact, their lifetime is comparable to that of the hadronic phase, and resonances are sensitive to effects such as rescattering and regeneration processes, which might affect the resonance yields and shape of the transverse momentum spectra. These processes can be studied...
Measurements of heavy quarkonium in heavy-ion collisions provide a powerful tool to study the properties of the Quark-Gluon Plasma (QGP). Due to the color screening effect, the dissociation of heavy quarkonium was proposed as a direct signature of the QGP formation. Compared to charmonia, bottomonia are cleaner probes because of negligible regeneration contribution at the top RHIC energy....
We shed a light on the nature of matter at extremely high baryon density and contrast it to hot QCD matter by using the trace anomaly as a measure of conformality. We discuss an interpretation that a peak in the sound velocity in high-density matter, as suggested by the neutron-star observational data, signifies strongly-correlated conformal matter. The normalized trace anomaly is a...
The information on the quarkonium production in heavy ion collisions is important to probe the heavy-quark dynamic in the quark-gluon plasma (QGP). The suppression of quarkonia production is particularly interesting since it comprises different in-medium effects such as color screening or recombination. But due to the inclusiveness of the nuclear modification factor used to quantify the...
We discuss the QCD phase diagram under the effects of heavy quarks and a magnetic field. The effect of the heavy-quark impurity is significantly enhanced by the quantum many-body effect called the QCD Kondo effect within a mean-field theory. Solving the gap equation, we find that the QCD Kondo condensate emerges due to the formations of a pairing between a light quark and a heavy quark. We...
At RHIC, a fireball forms in the Au-Au collision and rapidly cools during expansion, inside which the QCD matter undergoes a phase transition from quark-gluon-plasma to the hadronic phase. The phase transition signals are expected to be observed via the measurements of fluctuations of conserved charges such as baryon numbers [1]. As the realistic fireball is a temporally fast evolving and...
Charmonia are excellent probes of deconfinement in heavy-ion collisions. Due to different binding energies between J/$\psi$ and $\psi$(2S),the hot nuclear matter effects have different impact on the production yields of the ground and excited states. The measurements of the J/$\psi$ and $\psi$(2S) in the same collision system will give an insight to the charmonium production mechanisms in...
A Large Ion Collider Experiment (ALICE) is an experiment at the Large Hadron Collider (LHC) which aims to understand the most basic properties of Quantum Chromodynamics (QCD) by observing Quark-Gluon Plasma (QGP) created at the center of relativistic heavy-ion collisions. The ALICE detector has been largely upgraded during the LHC Long Shutdown LS2 to become capable of collecting Pb-Pb...
The external-target experiment (CEE) is the first large-scale nuclear physics experimental device by China to operate in the fixed-target mode with an energy of ∼ 1 GeV. The purpose of the CEE is to study the properties of dense nuclear matter. CEE uses a multi-gap resistive plate chamber (MRPC) as its internal time-of-flight (iTOF) detector for the identification of final-state particles. An...
Several previous studies imply that the quark anomalous magnetic moment (AMM) is dynamically generated through the spontaneous chiral symmetry breaking in the low energy QCD. Even though the exact form of the quark AMM still remains unclear, the AMM would be an essential ingredient for quark matter properties and QCD phase diagram under external magnetic field.
In this talk, I will discuss...
