Gauge kinetic term
= Gauge kinetic term
{title2=$-\tfrac14F_{\mu\nu}F^{\mu\nu}$}
The field-strength quadratic term supplies gauge-field dynamics. In the canonical Abelian normalization it is $-F_{\mu\nu}F^{\mu\nu}/4$; a non-Abelian theory includes the invariant sum or trace over internal indices. A vector mass inferred from a scalar kinetic term is physical only after specifying this normalization.