with the charged lepton mass terms given by ψ ψ ¯ ¯ Φ Φ 2 ψ ψ . Such a potential is minimised when the masses fit the Koide formula. Minimising does not give the mass scale, which would have to be given by additional terms of the potential, so the Koide formula might indicate existence of additional scalar particles beyond the Standard Model's Higgs boson.