 Due to its complexity, this Lagrangian is best described by breaking it up into several parts as follows.The kinetic term formula_24 contains all the quadratic terms of the Lagrangian, which include the dynamic terms (the partial derivatives) and the mass terms (conspicuously absent from the Lagrangian before symmetry breaking)

where the sum runs over all the fermions of the theory (quarks and leptons), and the fields formula_26, formula_27, formula_28, and formula_29 are given as

with ‘formula_31’ to be replaced by the relevant field (formula_32, formula_33, formula_34), and by the structure constants of the appropriate gauge group.The neutral current formula_35 and charged current formula_36 components of the Lagrangian contain the interactions between the fermions and gauge bosons,
where formula_38 The electromagnetic current formula_39 is

where formula_41 is the fermions' electric charges.