Tetraquark bound states in a Bethe-Salpeter approach

Understand

We determine the mass of tetraquark bound states from a coupled system of covariant Bethe-Salpeter equations.

• Similar in spirit to the quark-diquark model of the nucleon, we approximate the full four-body equation for the tetraquark by a coupled set of two-body equations with meson and diquark constituents.
• These are calculated from their quark and gluon substructure using a phenomenologically well-established quark-gluon interaction.
• For the lightest scalar tetraquark we find a mass of the order of 400 MeV and a wave function dominated by the pion-pion constituents.