First-order diagrams for the decays, where and can be a gauge boson pair, a fermion-antifermion pair, a gauge-Higgs boson pair, or a pair of Higgs bosons. The strong decay mode is also allowed but not shown above. The (a), (b), and (c) diagrams denote decays via , , or exchange in the -channel, while (d) and (e) correspond to the decays involving quark exchange in the - and -channels. Figure from [30].
