An equation with Feyman diagrams inside

Disclaimer: I'm an absolutely sporadic user of TikZ and I have no experience whatsoever in drawing Feynman diagrams with it (I still use feynmp for that...) but here's a shot at it

documentclass{article}

usepackage{tikz}

% tikz picture vertically centered on math axis
newcommand*{ctikz}[2][]{hbox{mathsurround=3pt$vcenter{hbox{tikz[#1]{#2}}}$}}
usetikzlibrary{arrows.meta}
newcommand*{I}{mathrm{i}}

begin{document}

[
Z[j] =
frac{displaystyle biggl[ 1 - frac{I,g}{4!} int 
      biggl(
      -3 ctikz{ draw(0,0)circle(0.2); draw(0.4,0)circle(0.2); }
      + 6I
        ctikz{
          draw[{Rays[]}-{Rays[]}](0,0)--(0.8,0);
          draw(0.4,0.2)circle(0.2);}
      + ctikz{
          draw[{Rays[]}-{Rays[]}](0.3,0.3)--(-0.3,-0.3);
          draw[{Rays[]}-{Rays[]}](-0.3,0.3)--(0.3,-0.3);}
      biggr)
      expbiggl(-frac{I}{2} int J Delta_{mathrm{F}} J biggr)biggr] mathrm{d}z}% end of numerator
     {displaystyle 1 - frac{I,g}{4!} int Bigl(-3 ctikz{draw(0,0)circle(0.2);draw(0.4,0)circle(0.2);}Bigr) mathrm{d}z}
]

end{document}