Heavy Tetraquarks in the Relativistic Quark Model

We give a review of the calculations of the masses of tetraquarks with two and four heavy quarks in the framework of the relativistic quark model based on the quasipotential approach and QCD. The diquark-antidiquark picture of heavy tetraquarks is used. The quasipotentials of the quark-quark and diquark-antidiquark interactions are constructed similarly to the previous consideration of mesons and baryons. Diquarks are considered in the colour triplet state. It is assumed that the diquark and antidiquark interact in the tetraquark as a whole and the internal structure of the diquarks is taken into account by the calculated form factor of the diquark-gluon interaction. All parameters of the model are kept fixed from our previous calculations of meson and baryon properties. A detailed comparison of the obtained predictions for heavy tetraquark masses with available experimental data is given. Many candidates for tetraquarks are found. It is argued that the structures in the di-J/ψ mass spectrum observed recently by the LHCb collaboration can be interpreted as ccc¯c¯ tetraquarks.

Higgs-Meson and Higgs-Gluon Interaction and Mass Acquiring Mechanism

The mass acquiring mechanism of meson or gluon is discussed in this article. Higgs-meson interaction and Higgs-gluon interaction are the key mechanism. Finally, we can get the mass origin of neutron or proton. The detail deduction is provided in the manuscript. We can get same mass of charged pions, neutral pion, charged gluons, and neutral gluons. This article solves the mass gap problem of Yang-Mills theory.

Electromagnetic transition form factors of baryons in a relativistic Faddeev approach

The covariant Faddeev approach which describes baryons as relativistic three-quark bound states and is based on the Dyson-Schwinger and Bethe-Salpeter equations of QCD is briefly reviewed. All elements, including especially the baryons’ three-body-wave-functions, the quark propagators and the dressed quark-photon vertex, are calculated from a well-established approximation for the quark-gluon interaction. Selected previous results of this approach for the spectrum and elastic electromagnetic form factors of ground-state baryons and resonances are reported. The main focus of this talk is a presentation and discussion of results from a recent investigation of the electromagnetic transition form factors between ground-state octet and decuplet baryons as well as the octet-only Σ0 to Λ transition.

Resonance contribution of scalar color octet to tt̄ production at the LHC in the minimal four-color quark–lepton symmetry model

The scalar color octet contribution to the resonance [Formula: see text]-pair production at the LHC is calculated and analyzed by taking into account the one-loop effective two-gluon vertex. It is shown that this contribution from the scalar color octet [Formula: see text] predicted by the minimal model with the four-color quark–lepton symmetry is for [Formula: see text] = 13 TeV of about a few percent for 750 [Formula: see text] 1800 GeV and can exceed 10% for 400 [Formula: see text] 750 GeV. It is also pointed out that the search for the scalar octet [Formula: see text] as the resonance in the dijet mass spectra seems to be difficult because of the smallness of its one-loop effective two-gluon interaction.

ON A POSSIBILITY TO ELIMINATE THE LANDAU POLE IN QCD

We apply the Bogoliubov compensation principle to QCD. The nontrivial solution of compensation equations for a spontaneous generation of the anomalous three-gluon interaction leads to the determination of parameters of the theory, including behavior of the gauge coupling αs(Q2) without the Landau singularity, the gluon condensate V2 ≃0.01 GeV 4, mass of the lightest glueball MG≃1500 MeV in satisfactory agreement with the phenomenological knowledge. The results strongly support the applicability of Bogoliubov compensation approach to gauge theories of the Standard Model.