tadpole diagram using tikz-feynman

Question

I want to draw the diagram with one loop. But my latex code is not working. let me be more specific

\documentclass{beamer}
\usetheme{Warsaw}
\usepackage{mathrsfs}
\usepackage{braket}
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{tikz-feynman}
\usepackage[compat=1.1.0]{tikz-feynman} 
\usepackage{simpler-wick}
\usepackage{slashed} 
\begin{tikzpicture}
\begin{feynman}
\vertex (a){\(1\)};
\vertex[right=2 cm of a ](b){\(2\)};
\vertex[below=2 cm of b] (c){\(B\)};
\vertex[left=2 cm of c](d){\(A\)};
\vertex[above=1cm of d](e);
\diagram*{
   (d)--(e)--[out=135,in=225](e)--(a), (c)--(b)
};
\end{feynman}
\end{tikzpicture}

so basically I have points a and d vertically connected. And point e which is the midpoint of line ad,there I want to draw a left side loop. but this gives error. although I get success using this code

 \feynmandiagram[inline=(c.base)vertical=a to b, layered layout]{
     a[particle=\(A\)]--c [dot] --[out=135, in=225, loop, min distance=2cm]c--b[particle=\(1\)] 
    };

but I want to draw loops under tikzpicture environment, feynman environment.

another thing I tried to run feynhand using the package \usepackage {tikzfeynhand}. but my compiler (texmaker) say it cannot find the feynhand style. tried to run feynhand in sharelatex. it also say the same.

please help.thanks

Answer 1

According to the manual, \diagram* should be kind of a last resort, meaning that you need to do all yourself. Here is a proposal.

\documentclass{beamer}
\usetheme{Warsaw}
\usepackage{mathrsfs}
\usepackage{braket}
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{tikz-feynman} 
\usetikzlibrary{calc}
\usepackage{cancel}
\begin{document}
\begin{frame}
\frametitle{A manually adjusted Feynman diagram}
\begin{overlayarea}{\textwidth}{\textheight}
\begin{tikzpicture}
\begin{feynman}
\vertex (a){\(1\)};
\vertex[right=2 cm of a ](b){\(2\)};
\vertex[below=2 cm of b] (c){\(B\)};
\vertex[left=2 cm of c](d){\(A\)};
\vertex[above=1cm of d](e);
\vertex[left=1cm of e](h);
\diagram*{
    (d)--(a), (e)--[out=135,in=90,min distance=0.5cm](h), 
    (e)--[out=-135,in=-90,min distance=0.5cm](h), (c)--(b)
};
\end{feynman}
\end{tikzpicture}
\begin{tikzpicture}
\begin{feynman}
\vertex (a){\(1\)};
\vertex[right=2 cm of a ](b){\(2\)};
\vertex[below=2 cm of b] (c){\(B\)};
\vertex[left=2 cm of c](d){\(A\)};
\vertex[above=1cm of c](e);
\vertex[right=1cm of e](h);
\diagram*{
    (d)--(a), (e)--[out=45,in=90,min distance=0.5cm](h), 
    (e)--[out=-45,in=-90,min distance=0.5cm](h), (c)--(b)
};
\end{feynman}
\end{tikzpicture}
\begin{tikzpicture}
\begin{feynman}
\vertex (a){\(1\)};
\vertex[right=2 cm of a ](b){\(2\)};
\vertex[below=2 cm of b] (c){\(B\)};
\vertex[left=2 cm of c](d){\(A\)};
\path (a)--(c) coordinate[pos=0.25] (e);
\coordinate (h) at ($(e)+(-{1/sqrt(2)},-{1/sqrt(2)})$);
\diagram*{
        (e)--[out=-180,in=135,min distance=0.5cm](h), 
    (e)--[out=-90,in=-45,min distance=0.5cm](h), (c)--(a),
    (d)--[draw=white,double=black,very thick](b)
};
\end{feynman}
\end{tikzpicture}
\begin{tikzpicture}
\begin{feynman}
\vertex (a){\(1\)};
\vertex[right=2 cm of a ](b){\(2\)};
\vertex[below=2 cm of b] (c){\(B\)};
\vertex[left=2 cm of c](d){\(A\)};
\path (b)--(d) coordinate[pos=0.25] (e);
\coordinate (h) at ($(e)+({1/sqrt(2)},-{1/sqrt(2)})$);
\diagram*{
        (e)--[out=0,in=45,min distance=0.5cm](h), 
    (e)--[out=-90,in=-135,min distance=0.5cm](h),
    (d)--(b), (c)--[draw=white,double=black,very thick](a)
};
\end{feynman}
\end{tikzpicture}

\end{overlayarea}
\end{frame}
\end{document}

As you see, you can get acceptable results this way, but it does require some effort.

As for tikzfeynhand, I never heard about this before, but you may download it from here. Looking at its manual it was rather amusing to see that this package also supports "Anti-Majorana fermions", which I previously thought were unique to tikz-feynman. This is a very funny oxymoron, but probably should not be part of any serious package that has not been released on April 1.