Form factors of $\Omega^-$ in a covariant quark-diquark approach

Abstract

The electromagnetic and gravitational form factors of $\Omega^-$, a spin-3/2 hyperon composed of three $s$ quarks, are calculated by using a covariant quark-diquark approach. The model parameters are determined by fitting to the form factors of the lattice QCD calculations. Our obtained electromagnetic radii, magnetic moment, and electric-quadrupole moment are in agreement with the experimental measurements and some other model calculations. Furthermore, the mass and spin distributions of $\Omega^-$ from the gravitational form factors are also displayed. It is found that the mass radius is smaller than its electromagnetic ones. Finally, the interpretations of the energy density and momentum current distribution are also discussed.