 The interaction of the gauge bosons and the fermions are through the gauge covariant derivative,
where the subscript runs over the three generations of fermions; , , and are the left-handed doublet, right-handed singlet up, and right handed singlet down quark fields; and and are the left-handed doublet and right-handed singlet electron fields.The Feynman slash formula_14 means the contraction of the 4-gradient with the Dirac matrices
and the covariant derivative is (excluding the gluon gauge field for the strong interaction)
Here formula_17 is the weak hypercharge and the formula_18 are the components of the weak isospin.The formula_19 term describes the Higgs field and its interactions with itself and the gauge bosons,

The formula_21 term describes the Yukawa interaction with the fermions, 
and generates their masses, manifest when the Higgs field acquires a nonzero vacuum expectation value, discussed next.