Higgs Boson Decays: Theoretical Status

The discovery of a Standard-Model-like Higgs boson at the LHC [1, 2] completed the theory of electroweak and strong interactions. The measured Higgs mass of (125.09 ± 0.24) GeV [3] ranges at the order of the weak scale. The existence of the Higgs boson [4–9] allows the Standard Model (SM) particles to be weakly interacting up to high-energy scales. This, however, is only possible for particular Higgs-boson couplings to all other particles so that with the knowledge of the Higgs-boson mass all its properties are uniquely fixed. The massive gauge bosons and fermions acquire mass through their interaction with the Higgs field that develops a finite vacuum expectation value in its ground state. The minimal model requires the introduction of one isospin doublet of the Higgs field and leads after spontaneous symmetry breaking to the existence of one scalar Higgs boson.