Effects of the one-gluon annihilation process on light diquonia

The spectra of all q2q¯2 systems composed of u, d, or s quarks are investigated in the framework of the nonrelativistic quark model (NRQM) using a Hamiltonian which takes into account the one-gluon annihilation process. The shift in energy due to this effect is studied as well as the mixing of different flavor states. A systematics over all the possible total spin and total isospin is carried out, while the total angular momentum is fixed at zero and the parity is the natural one. The four-body problem is solved by the variational method in harmonic oscillator bases including all configurations up to six quanta. The problems arising from the calculation of pure relativistic mechanisms in the NRQM are discussed. The contribution of the one-gluon annihilation process to the structures of light diquonia is found quite weak but non-negligible. A possible model to include other annihilation mechanisms is proposed.