gg states in the Bethe-Salpeter equation under the covariant instantaneous Ansatz

A. 3D form (under the Covariant Instantaneous Ansatz) of the Bethe-Salpeter Equation (BSE) with a Lorentz-invariant, spin-dependent confining kernel is made use of to study the low-lying (L = 0, 1) gg states and derive their spectrum. This Covariant Instantaneous Ansatz (CIA) is a natural Lorentz-invariant generalization of the standard Instantaneous Ansatz (IA). The constituent gluon mass, m(g), is the free parameter used in this model. The sensitivity of the gluonium spectrum to m(g) is studied. Comparison of predictions of some gg states is done with those of other models and some experimental candidates.