| Speaker | Title | Abstract |
| Sinya Aoki | Difficulties in the direct method for two baryon systems in lattice QCD | I report current status for two baryon systems in lattice QCD. After brief introduction of the issue, I explain why two baryon systems are difficult to investigate in lattice QCD, and point out problems in the direct method, which calculates the energy of two baryons in the finite box. In particular, I show that results claiming the existence of both deuteron and di-neutron at heavy pion masses indeed suffer from these difficulties. |
| Hua-Xing Chen | Hidden-charm multiquark in QCD sum rules | |
| Takashi Ezoe | Kaon-Nucleon systems in the Skyrme model | We have investigated the kaon-nucleon systems by a modified bound state approach where we change the ordering of the variation and the projection from that of the Callan-Klebanov bound state approach. In this talk, we discuss the properties of the kaon-nucleon bound states, scattering states, and their potentials. |
| Takumi Doi | Baryon-Baryon Interactions from Lattice QCD | I will review the recent activities to calculate baryon-baryon interactions from lattice QCD. In particular, I will present the latest results obtained at (almost) physical quark masses. |
| Lisheng Geng | Towards a relativistic formulation of nucleon-nucleon interaction in chiral perturbation theory | We develop a new covariant scheme to construct the nucleon-nucleon interaction in chiral effective field theory motivated by the successes of relativistic theories in studies of atomic and nuclear systems and the strong need for a covariant chiral force in {\it ab initio} nuclear structure calculations. We start from the covariant chiral Lagrangians, keep the full form of Dirac spinors, and use naïve dimensional analysis to determine the Weinberg chiral dimension. At leading order, Lorentz covariance induces all the six invariant spin operators needed to describe the nuclear force, while a non-relativistic formulation only introduces three of them. A detailed investigation of the structures of the partial wave potentials hints at a better description of the scattering phase shifts. This is numerically verified by resuming the chiral potential in a three-dimensional reduction of the Bethe-Salpeter equation and fixing the five low energy constants by fitting the partial wave phase shifts. The description turns out to be quite good, particularly for $^1S_0$, $^3P_0$, and $^1P_1$-waves, much better than leading order Weinberg approach and similar to that of the next-to-leading order. |
| Atsushi Hosaka | Decays of low lying charmed baryons | We discuss decays of charmed baryons, which emit low energy pions. The basic pion-quark interaction is determined by chiral symmetry. The resulting decay rates reflect well the structure of the baryons, which turns out to be useful for the determination of the structure. |
| Yoichi Ikeda | Zc(3900) from lattice QCD | I will present recent results on Zc(3900) in J^P=1^+ studied by lattice QCD simulation at mpi > 400 MeV. We derive the s-wave coupled-channel potential in the pi J/psi-rho eta_c - DbarD* system from LQCD and calculate the observables such as invariant mass spectra and pole positions. It turns out that the nature of Zc(3900) is threshold cusp at at mpi > 400 MeV. |
| Kai-Wen Li | Hyperon-nucleon scattering in a covariant chiral effective field theory approach | Motivated by the successes of covariant baryon chiral perturbation theory in one-baryon and heavy-light systems, we propose a new, covariant approach for baryon-baryon interactions in chiral effective field theory. Based on the covariant chiral Lagrangian, the small component of the baryon spinor is retained in deriving the potential. Contrary to Weinberg's approach, the Kadyshevsky equation is solved to iterate the potential in order to include as many as relativistic effects. The scheme is applied to strangeness S=-1 hyperon-nucleon systems at leading order with 12 low energy constants. We obtain a $\chi^2$ around 17 by fitting to the 36 hyperon-nucleon scattering data, which is comparable with the advanced phenomenological models and next-to-leading order Weinberg's approach. The results indicate a better convergence of our new scheme. |
| Bingwei Long | A charming trap for pions | Charmed baryon resonance Lambda_c(2595) is about only a couple of MeVs above the pi-Sigma_c threshold, indicating that a Sigma_c attracts strongly a pion when the pion is very soft. I investigate the existence of more complicated structure due to this strong attraction. The first system under study is the three-body system of pi pi Sigma_c. It is found that there exists a shallow resonance close to the threshold, with quantum numbers isospin 1, spin 1/2, and positive parity. |
| Hiroyuki Noumi | Studies of exotic baryons with hadron beams at J-PARC | I will introduce some experimental efforts on exotic baryons at J-PARC. In particular, I would like to discuss what we can learn from data observed or to be observed. |
| Keisuke Ohtani | Lambda_c baryon in nuclear matter from QCD sum rule | We will discuss the mass modification of Lambda_c in nuclear matter. QCD sum rule analysis shows that in-medium modification of Lambda_c is strongly correlated to the modification of diquark. It is found that, as the density increases, the mass increases. |
| Kenji Sasaki | Strangeness S=-2 baryon-baryon interactions from Lattice QCD | |
| Chengping Shen | Recent exotic results at BESIII / Recent exotic results at BESIII and Belle, and Belle II status and plans | |
| En Wang | The study of the pentaquark in the unitary chiral approach | We have studied the reactions $\Lambda_b\to J/\psi \pi^−p$, $\Lambda_b\to J/\psi K0\Lambda$ and $\Xi_b^−\to J/\psi K^− \Lambda$ considering the light meson baryon interactons with the coupled channels and the $J/\psi p$ or $J/\psi \Lambda$ interactions. Taking into account the fact that there are predictions for a hidden-charm state without or with strangeness that couples to $J/\psi p$ or $J/\psi \Lambda$， we show that a neat peak/dip can be observed in the $J/\psi p$ or $J/\psi \Lambda$ invariant mass distribution, rather stable under changes of unknown magnitudes. |
| Shigehiro Yasui | Kondo effect for charm hadrons in nuclear medium | We discuss the properties of charm hadrons in nuclear medium by considering the heavy quark spin symmetry as the symmetry of QCD. We discuss the D meson and nucleon interaction in vacuum and its modifications in the nuclear medium. We will show that the D meson exhibit the Kondo effect at zero temperature. |