The meson cloud distributions in $r$-space are extracted from the nucleon electromagnetic and axial form factors which are derived in the perturbative chiral quark model. The theoretical results indicate that the electric charge and axial charge dist
ributions of the three-quark core are the same, the magnetic charge distributions of the meson cloud and three-quark core are more or less in the same region and peak at distances of around 2 $rm GeV^{-1}$, but the axial charge meson cloud distributes mainly inside the three-quark core.
The axial form factor as well as the axial charge of octet baryons are studied in the perturbative chiral quark model (PCQM) with the quark wave functions predetermined by fitting the theoretical results of the proton charge form factor to experiment
al data. The theoretical results are found, based on the predetermined quark wave functions, in good agreement with experimental data and lattice values. This may indicate that the electric charge and axial charge distributions of the constituent quarks are the same. The study reveals that the meson cloud plays an important role in the axial charge of octet baryons, contributing 30%-40% to the total values, and strange sea quarks have a considerable contribution to the axial charge of the $Sigma$ and $Xi$.
The electromagnetic properties of baryon octet are studied in the perturbative chiral quark model (PCQM). The relativistic quark wave function is extracted by fitting the theoretical results of the proton charge form factor to experimental data and t
he predetermined quark wave function is applied to study the electromagnetic form factors of other octet baryons as well as magnetic moments, charge and magnetic radii. The PCQM results are found, based on the predetermined quark wave function, in good agreement with experimental data.
We study the reaction $e^+e^-tobar DD$ near threshold in the $^3P_0$ non-relativistic quark model, including as intermediate states the $J/psi$, $psi(2S)$, $psi(3770)$ and $psi(4040)$ mesons. The work reveals that experimental data strongly favor one
of the two $psi(2S)-psi(3770)$ mixing angles derived by fitting to the $e^-e^+$ partial decay widths of the $psi(2S)$ and $psi(3770)$ mesons. The meson $X(3940)$ as well as the resonance around 3.9 GeV observed by Belle and BaBar Collaborations in the reaction $e^+e^-rightarrow bar DD$ is unlikely to be a $cbar c$ $I^G(J^{PC})=0^-(1^{--})$ state.
The investigation in the work of the reaction electron-positron to omega and pi0 mesons in the 3P0 nonrelativistic quark model reveals that the reaction electron-positron to omega and pi0 mesons process at the energy region from the omega and pi meso
ns threshold to 2.0 GeV is dominated by the two-step process in which the primary quark-antiquark pair first forms rho and rho mesons and then the vector mesons decay into omega and pi. With rho(1450) and rho(1700) mainly in 2S and 1D states respectively, the experimental data for the cross section of the reaction electron-positron to omega and pi0 mesons are well produced in the 3P0 quark model. The work supports the argument that rho(1450) is mainly a 2S meson and rho(1700) a 1D meson.
The antiproton-deuteron atoms are studied in models of various realistic, popular nucleon-antinucleon potentials. The small energy shifts and decay widths of the atoms, which stem from the short-ranged strong interactions between the antiproton and d
euteron, are evaluated in a well-established, accurate approach based on the Sturmian functions. The investigation reveals that none of the employed potentials, which reproduce the nucleon-antinucleon scattering data quite well, is able to reproduce the experimental data of the energy shifts of the 2p antiproton-deuteron atomic states. The energy shifts of the 2p antiproton-deuteron atomic states are very sensitive to the nucleon-antinucleon strong interactions, hence the investigation of the antiproton-deuteron atoms is expected to provide a good platform for refining the nucleon-antinucleon interaction, especially at zero energy.
The reactions $Sigma_b^* to Lambda_b pi$, $Sigma_b to Lambda_b pi$, and $Xi_b^* to Xi_b pi$ are studied in the $^3P_0$ non-relativistic quark model with all the model parameters fixed in the sector of light quarks. The theoretical predictions for the
decay widths $Gamma_{Sigma_b^* to Lambda_b pi}$ and $Gamma_{Sigma_b to Lambda_b pi}$ are consistent with the experimental data of the CDF Collaboration. Using as an input the recent mass of $Xi_b$ and the theoretical predictions mass of $Xi_b^{*}$, a narrow decay width about 1 MeV is predicted for the bottom baryon $Xi_b^*$. The work suggests that the $^3P_0$ quark dynamics is of independence of environments where heavy quarks may or may not be a component of baryons.
