Using a relativized diquark model Hamiltonian, we calculate the masses of $$J^{PC}=0^{++}$$J PC = 0 + + ground-state tetraquarks in the following systems: $$b s {\bar{b}} {\bar{s}}$$b s b ¯ s ¯ , $$bb {\bar{n}} {\bar{n}}$$b b n ¯ n ¯ ( $$n=u, d$$n = u , d ), $$bb {\bar{s}} {\bar{s}}$$b b s ¯ s ¯ , $$cc{\bar{c}} {\bar{c}}$$c c c ¯ c ¯ , $$b b {\bar{b}} {\bar{b}}$$b b b ¯ b ¯ , $$b c{\bar{b}} {\bar{c}}$$b c b ¯ c ¯ and $$b b {\bar{c}} {\bar{c}}$$b b c ¯ c ¯ . We also compute extensive spectra for the fully-heavy quark flavour combinations. Finally, as a test of the diquark model approach, we compute the masses of fully-heavy baryons in the diquark model. Our results may be compared soon to the forthcoming experimental data for fully-heavy three-quark systems.

We carry out a comprehensive survey of electromagnetic form factors of all light, heavy, and heavy-light ground-state pseudoscalar and scalar mesons. Our analysis is based upon a Schwinger-Dyson equations treatment of a $\mathrm{vector}\times \mathrm{vector}$ contact interaction. It incorporates confinement and ensures axial vector and vector Ward-Takahashi identities are satisfied along with the corresponding corollaries such as the Goldberger-Treiman relations. The algebraic simplicity of the model allows us to compute the form factors at arbitrarily large virtualities of the probing photon momentum squared with relative ease. Wherever possible and insightful, we compare our results for the electromagnetic form factors and the charge radii with those obtained earlier through Schwinger-Dyson equations, lattice, and with experimental observations available. We also comment on the scope and shortcomings of the model.

We present a detailed survey of electric, magnetic, and quadrupole form factors of light and heavy spin-1 vector mesons. It complements our analogous analysis of the electromagnetic form factors of pseudoscalar and scalar mesons reported earlier. Our formalism is based upon the Schwinger-Dyson equations treatment of a vector × vector contact interaction and the Bethe-Salpeter equation description of relativistic two-body bound states. We compute the form factors, associated moments, and charge radii, comparing these quantities to earlier theoretical studies and experimental results if and when possible. We also investigate the quark-mass dependence of the charge radii and find the anticipated hierarchy such that it decreases with increasing dressed quark masses. In addition, our analysis shows that the magnetic moment is independent of the mass of the light and heavy mesons. Our results agree with most measurements reported earlier, finding a negative quadrupole moment, implying the charge distribution is oblate. Published by the American Physical Society 2024

The extraction of elastic form factors for mesons in the context of the contact interaction model is revisited in this manuscript. The dressed masses of quarks and mesons are determined through the gap and Bethe-Salpeter equations. The generic elastic scattering process $M\gamma \to M$ is studied for the meson $M$ formed of two differently flavored quarks. The charge radii of scalar, pseudoscalar, vector and axial-vector mesons are also extracted by virtue of explicit calculation of the meson elastic form factors.

We study the evolution of light quarks with isospin symmetry and the pion masses in the presence of a thermal bath and study their temperature dependence. In addition, we analyze the inclusion of a coupling with temperature dependence. We attempt to study the dissolution of bound-states at temperatures higher than the critical temperature, but we found that the model shows that the bound-state's mass increases. We base our study on a momentum-independent symmetry-preserving truncation scheme contact interaction in the Schwinger-Dyson equations framework.