Gravitational form factors of pseudoscalar mesons in a contact interaction

Given the unique role played by the gravitational form factors (GFFs) in unraveling the internal mechanics of hadrons, we examine the GFFs of ground state pseudoscalar mesons z, rlg, rlb and the hypothetical strangeonium rls(ss<overline>). We adopt the coupled framework of Dyson-Schwinger and BetheSalpeter equations within a contact interaction and employ a novel approach to the dressed amputated meson-meson scattering amplitude, which makes connection with the energy-momentum tensor and with the GFFs. The resulting GFFs fulfill the anticipated symmetry constraints. The corresponding charge and mass radii and the D term are also computed. We show that the D term for the pseudoscalar mesons is bounded within the (-1; -1/3) range; these bounds correspond to the massless (chiral limit) and infinitely massive cases, respectively. Considering the current interest in the GFFs, understanding the D term of pseudoscalar mesons and their GFFs can provide an important first step for future endeavors in the field.