The HAL computations suggest the ``two-pion exchange potential'' at (semi-)long range regime. In this talk I introduce its theoretical development and explain my ideas.
The scattering states of the double-charmonium, such as $J/\psi J/\psi$, $\eta_c J/\psi$, and $\eta_c\eta_c$, are investigated by a simplified quark cluster model focusing on the Pauli principle over the quarks.
We found that its effects on the $c\bar cc\bar c$ quark system can be expressed by a two-meson potential, which has a long-range repulsion with a short-range attraction.
This...
Recent accelerator experiments have reported unexpected states known as exotic hadrons, whose properties cannot be explained by the conventional picture. In the heavy quark sector, $XYZ$, $T_{cc}$, $P_c$ etc. have been reported since the discovery of $X(3872)$. Many exotic hadrons are located near the hadron threshold, and thus hadronic molecular structures have been considered. In this talk,...
Elucidating the nature of exotic hadrons is one of the central challenges in hadron physics. In recent years, numerical simulations based on lattice QCD have become a powerful tool for investigating these hadrons from first principles. The HAL QCD method, which explores hadron interactions in lattice QCD through interaction potentials, has demonstrated particular advantages for systems...
The HAL QCD method has been established as a reliable method to study hadron-hadron interactions. However, in the $\bar{K} N$ potential, which dynamically generates the $\Lambda (1405)$ as the bound state, singular behavior around the origin has been observed. In order to clarify the cause of such behavior in the HAL QCD method, we calculate the R-correlators and local potentials in an...
I will summarize main points of the following two works.
[1] S. Ampuku, Y. Yamaguchi and M. Harada, [arXiv:2511.13003 [hep-ph]].
We develop a model that incorporates mixing between hadronic-molecular and compact multiquark components. We then apply this framework to the specific case of the Tcc and analyze the peak structure in the D0-D0-pi+ invariant-mass spectrum reported by LHCb. We find...
The $\bar{D}N$ system is one of the most fundamental systems involving charmed mesons and nucleons. However, experimental data are scarce, and effective models do not constrain the low-energy scattering parameters well. I will report the results of my analysis on the "HAL-conf-2023" LQCD data concerning the $\bar{D}N$ channel.
The femtoscopic study using the momentum correlation function from the high-energy collisions provides new insights for the hadron interactions. The correlation function is known to be sensitive to the low-energy interaction and the particle emission source. In addition, the femtoscopy approach is advantageous for the charm sector which is not easily studied by the traditional scattering...
We study the D\bar{D}^, DD^, and B\bar{B}^* correlation functions and discuss the structure of the associated exotic hadrons.
Recently, femtoscopy has gathered attention as a new approach to
access hadron--hadron interactions through momentum correlation functions. In particular, the $s$-wave interaction has been extensively discussed in the field. In this talk, we discuss the effect of interactions in higher partial waves on the femtoscopic correlation function. We first attempt to extend existing $s$-wave...
It has been discussed for a long time that light flavors, i.e., up, down and strangeness, give a variety of exotic hadrons. One of the most important examples are scalar mesons and glueballs. In this talk, we discuss these better-known light exotic particles from new perspectives. Firstly, we discuss a new framework for inner-structures of scalar mesons, and propose to study them by...
I will show some preliminary results on doubly bottom tetra quark states.
In the vacuum of ordinary QCD, the lightest hadron is the pion, which is an isotriplet pseudoscalar meson. This can be shown using QCD inequalities, if we assume that the theory possesses gamma_5 Hermiticity and that disconnected diagrams do not contribute. However, in the finite-density regime, gamma_5 Hermiticity is lost, and this argument no longer holds. In contrast, in two-color QCD, an...
