This 24 is a real representation, so the last two terms need explanation. Both formula_42 and formula_43 are complex representations. However, the direct sum of both representation decomposes into two irreducible real representations and we only take half of the direct sum, i.e. one of the two real irreducible copies. The first three components are left unbroken. The adjoint Higgs also has a similar decomposition, except that it is complex. The Higgs mechanism causes one real HALF of the formula_42 and formula_43 of the adjoint Higgs to be absorbed. The other real half acquires a mass coming from the D-terms. And the other three components of the adjoint Higgs, formula_46 and formula_47 acquire GUT scale masses coming from self pairings of the superpotential, formula_48