No Arabic abstract
In this paper an analytical description of the hadron-hadron scattering is presented by using PMD-SQS-optimum principle in which the differential cross sections in the forward and backward c.m. angles are considered fixed from the experimental data. Experimental tests of the PMD-SQS-optimal predictions, obained by using the available phase shifts, as well as from direct experimental data, are presented. It is shown that the actual experimental data for the differential cross sections of all principal hadron-hadron [nucleon-nucleon, antiproton-proton, mezon-nucleon] scatterings at all energies higher than 2 GeV, can be well systematized by PMD-SQS predictions.
In this paper an analytical description of spin-effects in hadron-hadron scattering is presented by using PMD-SQS-optimum principle in which the differential cross sections in the forward and backward c.m. angles are considered fixed from the experimental data. The experimental tests of the optimal predictions, obtained by using the available phase shifts, are discussed.
Coupled-channel dynamics for scattering and production processes in partial-wave amplitudes is discussed from a perspective that emphasizes unitarity and analyticity. We elaborate on several methods that have driven to important results in hadron physics, either by themselves or in conjunction with effective field theory. We also develop and compare with the use of the Lippmann-Schwinger equation in near-threshold scattering. The final(initial)-state interactions are discussed in detail for the elastic and coupled-channel case. Emphasis has been put in the derivation and discussion of the methods presented, with some applications examined as important examples of their usage.
Exclusive production of charmonium-like XYZ states in hadron-hadron ultraperipheral collisions(UPCs) and electron-proton scattering is studied employing effective Lagrangian method. Total cross sections and rapidity distributions of charmonium-like XYZ states are obtained in hadron-hadron UPCs and electron-proton scattering process. These predictions can be applied to estimate the observed event number of exclusive charmonium-like XYZ states in hadron-hadron UPCs and electron-proton scattering. The results indicate that it is significant to search $X(3872)$ and $Z^+_c(3900)$ in pA UPCs and Electron-Ion Collider in China will be an advantage platform to observe XYZ states in the future.
In this paper a measure of complexity of the system of angle-angular momentum quantum states produced in hadronic scattering is introduced in terms of the scattering entropies. We presented strong experimental evidence for the saturation of the entropic optimal limits in the pion-nucleon and kaon-nucleon scatterings. The validity of a principle of minimum complexity in hadronic interaction is supported with high accuracy (CL>99%) by the experimental data on pion-nucleon especially at energies higher than 2 GeV.
Many charmonium-like and bottomonium-like $XYZ$ resonances have been observed by the Belle, Babar, CLEO and BESIII collaborations in the past decade. They are difficult to fit in the conventional quark model and thus are considered as candidates of exotic hadrons, such as multi-quark states, meson molecules, and hybrids. In this talk, we first briefly introduce the method of QCD sum rules and then provide a short review of the mass spectra of the quarkonium-like tetraquark states and the heavy quarkonium hybrids in the QCD sum rules approach. Possible interpretations of the $XYZ$ resonances are briefly discussed.