Scalar self-energy
= Scalar self-energy
{title2=$\Sigma(p^2)$}
The two-point, one-particle-irreducible correction for a <scalar field>. With an insertion denoted $-i\Sigma(p^2)$, the full <scalar propagator> is $i/[p^2-m^2-\Sigma(p^2)+i0]$. A divergent coefficient of $p^2$ requires <wave-function renormalization>; a momentum-independent divergent term requires a <mass counterterm>.