I will discuss the effects on chiral symmetry breaking in the vector mesons mass. This is accomplished by separating the four quark operators appearing in the vector and axial vector meson sum rules into chiral symmetric and symmetry breaking parts depending on the contribution of the fermion zero modes. We then identify each part from the fit to the vector and axial vector meson masses. By...
Kaonic nuclei give us a good opportunity to study the interaction between anti-kaon and nuclei. Recently, the existence of three-body kaonic nuclei, the K-pp bound state, was confirmed in several experiments in J-PARC. In those experiments, kaon and pion beams were used to produce the K^-pp bound state. As a complementary probe, photo-induced reaction is important to study the production...
Systems as K−p and baryon–antibaryon (BBbar) are both characterised by the presence, already at the production threshold, of strong inelastic channels which can affect the properties and the formation of bound states and resonances.The Λ(1405), just below the antikaon-nucleon (KbarN) threshold, arises from the interplay between the KbarN and the coupled Σπ channel. This resonance is currently...
The low-energy neutron-neutron scattering has been studied by analyzing the final $nn$ interactions in $nd\to nnp$ ($n$,$p$,$d$ are neutron, proton and deuteron, respectively) and $\pi^- d\to nn \gamma$ data. The resulting neutron-neutron scattering length ($a_{nn}$) differs from the proton-proton one ($a_{pp}$), indicating the charge symmetry breaking of the nuclear force. However, the...
The mass of a nucleon consists of chiral variant and invariant components. Since their medium properties are different, the composition can be examined through matter in extreme conditions. For this purpose neutron stars are one of the ideal laboratories. Using a parity double model for nuclear matter, we study the mass composition of nucleons through construction of neutron star equations...
The topological susceptibility is a crucial probe in studying the QCD theta-vacuum structure and the axial anomaly. So far, some analyses on the topological susceptibility have been done based on chiral effective models. However, the flavor singlet nature for the theta-parameter has not been taken into account, so that the topological susceptibility in the previous studies would have a lack of...
The “Facility for Antiproton and Ion Research” (FAIR) is an accelerator-based international research, which presently is under construction in Darmstadt, Germany. The PANDA experiment intends to do basic physics research on various topics around the weak and strong forces, exotic states of matter and the structure of hadrons by colliding stored antiprotons with nuclear targets. Since the...
The next phase of hypernuclear experiment with heavy ion beams proceeding the HypHI experiment will contribute to solve two significant puzzles in few-body physics, that are revealed by the results of the HypHI Phase-0 experiment at GSI Helmholtz Centre for Heavy Ion Research (Darmstadt, Germany) in 2009. The first puzzle is on the possible unprecedented existence of the nnLambda (two neutrons...
Recently the $\Omega N\left(^{5}S_{2}\right)$ and the $\Omega\Omega\left(^{1}S_{0}\right)$ interacting potentials at nearly physical quark masses ($m_{\pi}\simeq$ 146 MeV and $m_k\simeq525$ MeV) has been calculated in the lattice QCD simulations by the HAL QCD Collaboration. Here, we explored hypothetical multi-strangeness nucleus $_{\Omega\Omega}^{6}He$ in $\Omega\Omega\alpha$ cluster model...
Recently exotic hadrons including a $c\bar{c}$ component have been reported in experimental researches. The exotic states cannot be explained by the ordinary hadron picture, namely a baryon as a three-quark state, and a meson as a quark-antiquark state, while a multiquark component would be dominated in their structure. Since the discovery of $X(3872)$ in 2003, the exotic mesons called $X$,...
We propose a new type of structure of single-heavy baryons made of one heavy and four light quarks, namely $Qqq\bar{q}q$ state, in addition to the conventional $Qqq$ state. It is proven that the inclusion of $Qqq\bar{q}q$ state is inevitable to explain the observed mass spectrum of heavy-quark spin-singlet and flavor-antisymmetric single-heavy baryons. Based on chiral symmetry of the light...
In this talk, we talk about our investigation on the heavy pentaquark states, found in the LHCb collaboration. With the coupled channel approach, and combined with the heavy quark spin symmetry and local hidden gauge symmetry, we study the coupled channel interactions of $\bar{D}^{(*)} \Sigma_c^{(*)}$ and $\bar{D}^{(*)} \Xi_c^{(*,\prime)}$, where threee $P_c$ states and $P_{cs}(4459) were...
The discovery of X(3872) by KEKB/Belle experiment opened new door in the hadron spectroscopy. After that, many charmonium and bottomonium like states which can not be identified as simple bound state of quark and anti-quark pair are discovered. In order to have concrete understanding of these hadrons, more detailed study such as determination of quantum number or measurement of decay branching...
The ordinary hadrons consist of two quarks for mesons or three quarks for baryons. The hadrons with the other structures such as the multi-quark states or the hadronic molecular states are called exotic hadrons. Here, we would like to determine the structure of exotic hadrons using the weak-binding relation for the near-threshold hadrons. In the weak-binding relation, we can determine...
In this talk I explain how we can evaluate the fractions of the pi N and other meson-baryon molecular/cloud components for the N and Delta resonances from the pi N scattering amplitude in terms of the compositeness. Then I construct a simple model to discuss the internal structure of the Roper resonance N(1440) with the meson-baryon compositeness.
I report on investigations of the baryon-baryon interaction for baryons with different flavors (strangeness, charm), based on chiral effective field theory (EFT). With regard to systems in the strangeness sector (Lambda-N, Sigma-N, Xi-N) the approximate SU(3) flavor symmetry of QCD is exploited to relate the interactions in those channels with each other and to the accurately known...
Hadrons interact via a residual strong force that is unmeasured for most hadron species. The measurement and quantitative understanding of the strong interaction among hadrons is considered to be one of the frontiers within the standard model of nuclear and particle physics. Scattering experiments and spectroscopy studies of stable and unstable nuclei allowed us to quantify the residual...
The strangeness S = −3 and −4 baryon-baryon interactions are investigated in the relativistic chiral effective-field theory at leading order. First, the 12 tree-level low-energy constants contributing to the S = −1 hyperon-nucleon interaction are fixed by fitting to the 36 hyperon-nucleon scattering data. Then the S = −3 and −4 baryon-baryon interactions are derived from that of S = −1...
Employing the covariant baryon chiral perturbation theory, we calculate the leading and next-to-leading order two-pion exchange (TPE) contributions to $NN$ interaction up to order $O(p^3)$. We compare the so-obtained $NN$ phase shifts with $2\leq L\leq 6$ and mixing angles with $2\leq J\leq6$ with those obtained in the nonrelativistic baryon chiral perturbation theory, which allows us to check...
We study the $\Lambda_c N$ interaction in the covariant chiral effective field theory (ChEFT) at leading order. All the relevant low-energy constants are determined by fitting to the lattice QCD simulations from the HAL QCD Collaboration. Extrapolating the results to the physical point, we show that the $\Lambda_c N$ interaction is weakly attractive in the $^1S_0$ channel, but in the $^3S_1$...
Heavy ion collisions at LHC energies offer a unique opportunity to study the formation of complex QCD bound states such as pentaquarks, tetraquarks, hadron molecules or multi-baryon states. Thermal and coalescence models are able to describe light nuclei and hypernuclei production in ultrarelativistic heavy ion collisions. Such theoretical scenarios can also be used to predict the production...
Recently, LHCb collaboration has reported three resonance states in the J/\psi p invariant mass spectrum from a weak decay of \Lambda_b. The states, P_c(4312), P_c(4440) and P_c(4457), are expected to be pentaquarks with flavor structure of uudc\bar{c}. In this work, we analyze the J/\psi p scattering by lattice QCD at m_\pi=700, 570, 410 MeV. We determine the spin-dependent J/\psi p...
I report the results for $\Omega(2012)$ and $Z_{cs}(3985)$ of Refs.[1,2]. We have studied the $\Omega(2012)$ which was measured in the Belle experiment. We conduct a study of the interaction of the $\bar K \Xi^*$, $\eta \Omega$($s$-wave) and $\bar K \Xi$($d$-wave) channels within a coupled channel unitary approach. We find that all data including the Belle experiment on $\Gamma_{\Omega^* \to...
In a recent paper \cite{Ablikim:2019pit}, the BESIII collaboration reported the so-called first observation of pure W-annihilation decays D+s→a+0(980)π0 and D+s→a00(980)π+. The measured absolute branching fractions are, however, puzzlingly larger than those of other measured pure W-annihilation decays by at least one order of magnitude. In addition, the relative phase between the two decay...
The first confirmed observation of a binary neutron star merger through its gravitational wave and associated electromagnetic emissions has opened a new window into understanding ultra-dense matter. In this talk I will describe recent progress in modeling the strong interaction physics of neutron stars and supernovae based on the low-energy realization of QCD, chiral effective field theory....
We estimate, for the first time, the $\Upsilon$ and $\eta_b$ mass shifts in symmetric nuclear matter. The estimate for the $\Upsilon$ is made using an SU(5) effective Lagrangian, studying the $BB$, $BB^*$, and $B^*B^*$ meson loop contributions for the self-energy. As a result, we include only the $BB$ meson loop contribution as our minimal prediction. As for the $\eta_b$, we include only the...
Results for $\eta_c$- and $J/\Psi$-nucleus bound state energies for various nuclei are presented. These results are obtained using effective Lagrangians at the hadronic level. Essential input for the calculations, namely the medium-modified $D$ and $D^{*}$ meson masses, as well as the density distributions in nuclei, are calculated within the quark-meson coupling (QMC) model. The attractive...
Despite the first two-baryon studies from lattice QCD being performed several decades ago, the parameters describing two-baryon interactions computed from various collaborations are still in tension. The many significant efforts from the community signal the difficulty of the problem at hand. Baryons suffer from a poor signal-to-noise ratio, often times leaving only a small window in which...
We have been promoting experiments to search for double hypernuclei using nuclear emulsion at KEK and J-PARC. Although not many samples have been interpreted in a unique way, they provide a glimpse of characteristics on two Lambda binding energies (B_LL) in the nucleus and the internal structure of the Xi hypernucleus. In this talk, we will focus on the atomic mass-number dependence of B_LL...
Study of eta'(958) meson property in nuclear medium is fascinating because it may probe into the mechanism of hadron mass generation. A large mass reduction of eta' meson in nuclear medium owing to its UA(1) anomaly is expected in several model calculations. If the eta' mass is reduced in a nucleus, the eta' meson and the nucleus can form a bound state. We searched for the eta'-nucleus bound...
We plan to conduct an experiment for exploring eta’-mesic nuclei by using the Wide Angle Shower Apparatus (WASA) detector at the fragment separator (FRS) in GSI. We aim at producing and observing eta'-mesic nuclei in 12C(p, dp) reaction by employing 2.5 GeV proton beams. We use the WASA detector to detect protons from decays of eta'-mesic nuclei and the FRS to measure the momenta of the...
An established approach for quantitative investigation of the partial restoration of chiral symmetry in finite density is study of deeply bound pionic atoms. We are planing to perform spectroscopy of pionic atoms via (d,3He) reaction at RIBF. In the next experiment using several tin isotopes as a target, we are intended to evaluate quantitatively density dependence of the quark condensate.
The existence of eta-mesic nuclei in which the eta meson is bound in a nucleus by means of the strong interaction was postulated more than 30 years ago, however, it has not been yet confirmed experimentally. The discovery of this new kind of an exotic nuclear matter would be very important as it might allow for a better understanding of the eta meson structure and its interaction with...
The ηd threshold structure has been experimentally studied in the γd→π0ηd reaction at incident photon energies ranging from the reaction threshold to 1.15 GeV. An enhancement is observed near the ηd threshold in dσ/dMηd. The measured angular distribution of deuteron emission dσ/dΩd<\sub> is rather flat, which cannot be...
In a recent work with Raquel Molina, and Natsumi Ikeno, we have found an explanation for the peak observed in the pn -> pi+ pi- d reaction (pi0 pi0 d) that has been associated to a dibaryon d*(2380) so far. A sequential mechanism of single pion production pn-> pp pi- followed by pp -> pi+ d (plus pn -> nn pi+ followed by nn -> pi- d) reproduces the observed peak in strength, position and...
The strong interaction theory in the low energy regime, is still missing fundamental experimental results in order to achieve a breakthrough in its understanding. Among these, the investigation of the low-energy kaon-nucleon/nuclei processes plays a key-role, with important consequences going from particle and nuclear physics to astrophysics. The kaon-nuclei interactions are being measured by...
I shall present experiments devoted to the study of the kaonic atoms at the DAFNE Collider at the LNF-INFN, Frascati (Roma) laboratory. Combining the excellent quality kaon beam delivered by the DANE collider in Frascati (Italy) with new experimental techniques, as fast and very precise X ray detectors, like the Silicon Drift Detectors, we have already performed unprecedented measurements in...
