We discuss the modification of the properties of heavy mesons under extreme conditions of density present in heavy-ion collisions at CBM/FAIR energies. We pay a special attention to the behavior of Tcc(3875) and Ds0(2317) as well as their corresponding antiparticles in a dense nuclear environment, so as to show that the charge-conjugation asymmetry in nuclear matter could become an interesting...
We summarize the relationship between chiral symmetry breaking and the masses of hadrons. Next, we discuss the behavior of vector mesons in matter. Finally, we demonstrate why K1 and K* are appropriate chiral partners that can be realistically measured in experiments.
Femtoscopy is a powerful technique for studying final-state interactions between hadrons, employing two- and three-body correlations to analyze the emission source and final-state interactions of particles with low relative momentum. Recent research by the ALICE collaboration has demonstrated the realization of a common baryon-baryon emission source in pp collisions, opening new avenues for...
Hadrons are elementary excitations of the QCD vacuum and reflect its fundamental properties. A large fraction of their mass originates from chiral symmetry breaking, which is expected to be partially restored under high-temperature or high-density conditions. In such environments, the modification of hadron mass spectra is expected.
To investigate in-medium modifications of hadron masses,...
We perform a numerical study in lattice QCD on $\Lambda(1405)$ in the flavor SU(3) limit. Previous studies based on the chiral symmetry have suggested that the spectrum corresponding to $\Lambda(1405)$ observed in experiments may be explained by a combination of two poles. To elucidate such property from lattice QCD, the HAL QCD method is employed, in which hadron interactions are extracted as...
The spectral functions of chiral partners should become degenerate when the QCD chiral symmetry is restored. The axial-vector spectra are experimentally more challenging to construct than those of vector mesons that directly couple to virtual photons and then to dileptons.
Chiral mixing of the vector with axial-vector mesons is thus a key phenomenon to probe in-medium modifications of vector...
Baryon-baryon interactions are crucial for understanding phenomena at nuclear length scales and beyond. Advances in lattice QCD have enabled detailed studies of these interactions, particularly at heavier quark masses. In this talk, I will present recent progress in the field, focusing on our work with systems entirely composed of charm quarks, including baryons and dibaryons. Utilizing...
The possibility of observing mass and width modifications of phi mesons in dense matter is an important tool to better understand the behaviour of strongly interacting matter in extreme conditions. Here, I used a BUU transport approach to examine the mass modification of phi mesons and its consequences on the dilepton and kaon invariant mass spectra in several proton-induced reactions with Cu...
In addition to the applicability of lattice simulations in dense medium, two-color QCD world has another advantage that diquark dynamics can be directly observed since diquarks are color-singlet for Nc=2. In this talk, first I explain how a chiral model, i.e., linear sigma model, for Nc=2 and Nf=2+1 is constructed. Then, based on it, I present diquark mass modifications at finite temperature...
Recently, there has been active research on how the properties of the $\phi$ meson change in nuclear matter. Understanding the $\phi$-nucleon interaction is essential for clarifying the behavior of the $\phi$ meson in a nuclear environment. Also, the $\phi$-$N$ interaction is a unique hadronic system where quark exchange is forbidden at the first order, making gluon exchange the dominant...
Compared to the strong interaction, the binding energy of the Coulomb interaction is about 1/1000, so it is usually neglected. However, the binding energy of Χ(3872) is extremely small compared to many other hadrons, suggesting that the effect of the Coulomb interaction must be considered. In this talk, we consider the bound state using Coulomb plus square well potential model. We numerically...
In hadron physics, the near-threshold exotic hadrons have been actively studied, motivated by the recent experimental reports. One of the possible internal structures of exotic hadrons is the hadronic molecular state, which is the composite state of two hadrons. The fraction of the hadronic molecular component in the wavefuction is called the compositeness [1]. Through an analysis of the...
Elucidating the mechanisms by which quarks and gluons are confined within hadrons is one of the most fundamental challenges in QCD. Addressing this problem requires an understanding of the role of non perturbative properties, such as chiral and gluon condensates, as well as the associated spontaneous and anomaly-induced symmetry breaking, in hadron formation. Recently, the stress distribution...
Multi-strangeness systems, such as $\Xi$ hypernuclei and double $\Lambda$ hypernuclei, are of crucial importance for understanding baryon-baryon interactions and
the nuclear matter equation of state. $Xi$-atoms, where a $\Xi^-$ is trapped in atomic states around a nucleus, is a good playground to investigate the optical potential
a $\Xi^-$ feels in nuclei and thus to study the $\Xi N$...
We study the electromagnetic and axial structure of the octet baryons in a nuclear medium in terms of the nuclear matter density $\rho$. The experimental information about the internal structure of baryons in nuclear medium is very scarce. Theoretical studies are then fundamental for the understanding of environments with dense nuclear matter, from the high energy nucleus-nucleus collisions to...
Near-threshold exotic hadrons are studied actively. In order to understand the nature of them, it is necessary to determine the scattering length from experimental data, because the scattering length governs the near-threshold scatterings. The cusp structure of cross sections reflects the value of the scattering length.
In this work, we study the behavior of threshold cusp in multi-channel...
I will summarize recent progress in the study of hadron-hadron interactions using lattice QCD near the physical pion mass (146 MeV), focusing on the HAL QCD method and its connection to experimental data. In particular, we highlight several key interaction channels: (i) Baryon-Baryon Interactions in the S=-2 sector, (ii) Meson-Meson Interactions in the D*-D (Tcc) channel, and (iii)...
The hyperon single-particle potential (hyperon potential) is a key ingredient for discussing the properties of hyperons in a dense environment, including their existence in neutron stars. In this talk, we will introduce the hyperon potential in nuclear matter based on the baryon forces within modern chiral effective field theory. We will then discuss the validity of these potentials by...
Hyperon-proton scattering experiment is one of the most direct methods to study the hyperon-nucleon (YN) interaction, as in the case of the NN interaction.
Although it had been experimentally difficult for a long time due to short lifetime of hyperons, we successfully performed high-statistics Σ±p scattering experiment at J-PARC.
More YN scattering data for various channels and observables...
This talk will cover preliminary results from E42 on the H-dibaryon search near the Lambda Lambda and Xi- p mass thresholds. The E42 has collected nearly seven thousand Lambda Lambda production events from (K-, K+) reactions off 12C at 1.8 GeV/c. We are approaching the final stage of data anlysis to open the box. The presentation will discuss the nature of the H-dibaryon with only a small...
"Treating the NAGARA emulsion event in a realistic L-L-4He three-body model, it is found that the LL6He -> H + 4He strong-interaction lifetime becomes much longer than hypernuclear weak-interaction decays for H dibaryon mass below m(L)+m(n), so that a deeply bound H is not in conflict with hypernuclear data.
Using EFT methods, it is found that the H -> nn weak-decay lifetime
for m(H) <...
"Recent theoretical and experimental studies have provided insights into the properties of the $\bar{K}N$ interaction. Theoretically, it has been argued that the formation of a molecular-like quasi-bound state, $\Lambda$(1405), arises from the strong attraction between $\bar{K}$ and nucleon with isospin I = 0 channel. Experimentally, the K-pp three-body system, the lightest Kaonic nucleus, was...
Nucleon-antinucleon interactions have been extensively studied. Recently, it is pointed out that the p-pbar enhancement and X(1835) resonance, observed in the BESIII experiment, may be related to low-energy nucleon-antinucleon interaction. We propose a new experiment of low-energy antineutron-proton scattering, which is free from the Coulomb interaction effect. We also address open questions...
"In recent years, as experimental data on the excited states of Xi, Xi(1620) and Xi(1690), have been collected, theoretical analyses have also been actively conducted.
In our previous study, we have constructed theoretical models with the chiral unitary method based on the Belle and ALICE results [1-3].
In this work, we classify the eigenstates in order to investigate the physical origin...
Since most hadrons are unstable, we study nature of hadrons using complex potentials. In general, an eigenmomentum of the system is expressed as a pole of the scattering amplitude that is analyticaly continued to the complex momentum plane. Bound states are described by real potentials and their pole appears on the positive imaginary axis. By using complex potentials, we can describe unstable...
The U(1) axial anomaly is a fundamental aspect of QCD, and its properties can be examined through topological susceptibility. Recent first-principle calculations, such as lattice QCD studies with two or three colors, have investigated the topological susceptibility at finite temperature and finite quark chemical potential. While these results are expected to provide valuable insights into the...
One of the most compelling topics in interaction studies in recent years is the investigation of the proton-deuteron (\textit{p-d}) system. This system is of particular interest because it involves interactions between three nucleons, as the deuteron is composed of both a proton and a neutron. Therefore, it serves as a valuable laboratory for exploring many-body physics. A widely used method...
One of the most effective techniques for investigating the mechanism of baryon production is the study of angular correlations between two particles. Angular correlations represent a convolution of various physical processes, such as mini-jets, Bose-Einstein quantum statistics, conservation of momentum, resonances, and other phenomena that contribute to the unique behavior observed for...
We calculate the $D_s$-, $B$-, $D$- and $K$-nucleus bound state energies and coordinate space radial wave functions by solving the Klein-Gordon equation in momentum space.
The attractive strong potentials for the mesons in nuclei are calculated from the mass shifts of these mesons in nuclear matter in the local density approximation.
The mass shift of the $B$, $D$, and $K$ mesons are...
[based on Phys.Rev.D 110 (2024) 114052 ]
We discuss the relation between the Koonin-Pratt femtoscopic correlation function (CF) and invariant mass distributions from production experiments. We show that the equivalence is total for a zero source-size and that a Gaussian finite-size source provides a form-factor for the virtual production of the particles. Motivated by this remarkable...
We study the possibility of the formation of mesons ($K,~D,~B$ as well as $\phi$, charmonia, and bottomonia) bound in atomic nuclei.
The open strange and open heavy flavor mesic-nuclei are studied using the mass modifications of the mesons in nuclear matter within the quark meson coupling model [1,2].
The hidden-flavor ($\phi$) meson-nucleus bound states are studied with the mass...
The correlation function between deuteron and Xi particles produced in high-energy nuclear collisions has attracted attention as a quantity that provides information on the spatial distribution of these particles and the interaction between them. The two-baryon and three-baryon forces acting on subsystems of the three-baryon system are considered as possible interactions, but the role of the...
We conducted high-precision pionic atom spectroscopy experiments at RIBF using the (d, 3He) reaction. A pionic atom is a system in which π- mesons are deeply bound to the atomic orbitals of nuclei by attractive Coulomb forces and repulsive strong forces.
Evaluation of the partial restoration of chiral symmetry in finite density has been successfully performed at GSI and RIBF. Both...
The photoproduction of π+π− pairs at forward angles has traditionally been attributed to Pomeron exchange. However, recent analyses of CLAS data at photon energies below 4 GeV reveal that for ∣t∣≳0.5 ~GeV^2, this mechanism alone fails to fully describe the observed angular moments. To address this, we develop a new theoretical model incorporating both two-pion and pion-nucleon resonant...
The $\eta^{\prime}$ meson has an extraordinary large mass among the light pseudo-scalar meson nonet.
The large mass is considered to originate from the non-trivial vacuum structure associated with chiral symmetry breaking and the axial U(1) anomaly in the QCD.
In a nuclear medium, where the chiral symmetry is partially restored, the mass reduction of the $\eta^{\prime}$ meson is predicted by...
Gluonic effects are important in etaprime physics. In this talk I shall discuss the role of gluonic degrees of freedom in possible etaprime bound states in nuclei as well as in the etaprime-nucleon interaction. If experiments see evidence for an etaprime bound state, how do we interpret that it in terms of gluon related parameters? Might the possible very narrow and close to threshold...
Recently, experimental studies of the kaon-induced reactions on deuteron and helium-3 were carried out at J-PARC. The former experiment reported a resonance pole below the KbarN mass threshold in the deduced S-wave KbarN scattering amplitude in the isospin = 0 channel [1]. The pole is naturally interpreted as a KbarN bound state. The latter experiment reported a bump structure below the KbarNN...
The HAL QCD method has been established as a reliable method to study hadron-hadron interactions. However, singular behavior around the origin has been observed in the Kbar N potential, which dynamically generates the Lambda(1405) as the bound state. In order to clarify the cause of such behavior in the HAL QCD method, we calculate the NBS wave functions and R correlators in an effective...
Until recently, it was widely believed that every hadron is a composite state of either three quarks or one quark and one antiquark. In the last 20 years, dozens of exotic heavy hadrons have been discovered, and yet no theoretical scheme has unveiled the general pattern. For hadrons that contain more than one heavy quark or antiquark, the Born-Oppenheimer approximation for QCD provides a...
The hypertriton ($^3_\Lambda \text{H}$) is the lightest Lambda-Hypernucleus, consisting of one proton, one neutron, and a Lambda.
Its mass and lifetime have been measured using emulsion techniques and heavy-ion collision experiments.
Their relationship has been observed to deviate from theoretical predictions, which is known as the 'hypertriton puzzle'.
The accuracy of measured...
In this talk I will present a method to compute the properties of dilute nuclear matter from quantum field theory at finite density. This approach provides a parameter-free calculation of the energy per particle of nuclear matter relying only on experimental nucleon-nucleon phase shifts. This method can be used to compute the equation of state of dilute symmetric and neutron matter. As...
Based on the recent findings of the pentaquark states and tetraquark states in the experiments, we exploit the coupled channel formalism to investigate the mass spectrum of these multiquark states. In our results, we explain the molecular nature for the Pc and Pcs states within the coupled channel interactions. Furthermore, we extrapolate our study to the meson systems with the strangeness,...
Topic of neutron skin is interesting aspect of nuclear physics. Experiments like NA61/SHINE, PREX II and others may give us data for deeper understanding of this area of physics, helping to improve the theory. Different elements of the theory, like slope parameter, can be explored better by both - simulations and experiment.
In my talk I would like to focus on the theoretical results related...
We study the properties of the hadron-hadron potentials and quark-antiquark potentials from the viewpoint of the channel coupling[1]. We introduce the effective hadron-hadron potential with coupled to the quark channel.
As an application, we construct a coupled-channel model of $c\bar{c}$ and $D\bar{D}$ to describe exotic hadron $X(3872)$[2].
To investigate the internal structure of the...
Relativistic nuclear collisions serve as a powerful tool for exploring the QCD matter in the vicinity of the quark-hadron crossover. We investigate diffusion dynamics in the hot and dense QCD matter based on the numerical hydrodynamic model with a state-of-the-art equation of state at finite densities.
We study the decays $\bar B^0 \to \bar K^0 \, X$, $B^- \to K^- \, X$, $\bar B^0_s \to \eta (\eta')\, X$, $\bar B^0 \to \bar K^{*0} \, X$, $B^- \to K^{*-} \, X$ , $\bar B_s^0 \to \phi \, X$, with $X \equiv X(3872)$, from the perspective of the $X(3872)$ being a molecular state made from the interaction of the $D^{*+} D^-, D^{*0} \bar D^0$ and $c.c.$ components. We consider both the external and...
Hypernucleus is a many-body system with strangeness and is an important probe for discussing nuclear matter based on SUf(3).
In recent years, there have been significant advancements in experimental and theoretical studies for few-body hypernuclei. Discussions of the charge symmetry breaking effect and Sigma mixing effect are currently underway.
The outline of K-long Facility (KLF) at Jefferson Lab will be presented. It has been approved by PAC48 to run for 200 days of the beamtime to measure CQM and LQCD predicted but not established dozens of hyperon states. This facility also allows to study hyperons in nuclei.
Motivated by recent advancements in tetraquark studies, we analyze the mass spectra and decay properties of singly bottom tetraquarks using the diquark-antidiquark formalism. By examining various internal quark configurations and color structures, we calculate the mass spectra within a non-relativistic framework. Additionally, several resonances are proposed as potential candidates for these...
In this study, we investigate the applications of a result derived from WKB theory, specifically the Segre-Fermi Rule in its non-relativistic form, within the context of bottom-up holographic QCD. The Holographic Segre formula enables us to compute decay constants based on the holographic confining potential. This data serves as a critical input for extracting quark mass from the decay width...
By solving the Lippmann-Schwinger equation, possible hadronic molecules in the $D^*\bar K$-$D\bar K^*$ coupled-channel system are investigated with the one-meson exchange potentials, where both vector and pseudoscalar mesons are considered as exchange particles. We find an S-wave virtual state with mass $M=2487$~MeV, and a resonance with $M=2759$ and width $\Gamma=18$~MeV. In the $D^* \bar K$...
We present updated and extended results mass shift and nuclear bound states pseudoscalar and vector mesons in nuclear matter and nuclei.
The mass shift for these mesons are computed using the quark-meson coupling model and effective lagrangians, while the nuclear bound state energies are obtained by solving the Schrödinger and Klein-Gordon equations with complex optical potentials, for a wide...
