A key issue in understanding hadron structure and quark confinement is the unquenching dynamics, i.e., quark-antiquark pair creation and annihilation in the hadrons. The exotic multi-quark states play an important role for the study of the unquenching dynamics. While the discoveries of exotic hadrons with heavy flavors convinced people the existence of multiquark states, the light quarks play...
This talk provides an overview of experimental searches for exotic baryon states, such as light pentaquark and hexaquark states, including $\Theta^+$, $P_{s\bar{s}}$, $P_{c\bar{c}}$, and $ H$-dibaryons, utilizing hadron beams. Special attention will be given to upcoming experiments at the hadron hall of J-PARC and the KLF at JLab. The talk will also highlight a proposed experiment to study...
In Belle II, various exotic and heavy hadrons can be produced in $e^+e^-$ collisions at and near the $\Upsilon(4S)$ resonance. I will report recent results from the Belle II experiment.
Two pion emission decays of radially excited quarkonia are investigated, including Upsilon(3S->1S, 2S; 2S->1S) and Psi(2S->1S). The coupling structure is of scalar-isoscalar type, and the strengths turn out to be in a similar order, implying a common mechanism in the couplings. Using transition matrix elements between these states, we obtain the J/psi-J/psi-2pi couplings, from which we...
We develop a reduced-profile maximum-entropy framework for reconstructing zero-skewness valence-quark generalized parton distributions from the proton and neutron electromagnetic form factors. Since elastic form factors constrain only x-integrated moments, the entropy functional is used as a regularizer within a low-dimensional profile ansatz. A numerical proof-of-concept shows that the...
