# TikZ-Feynman

Ti*k*Z-Feynman is a LaTeX package allowing Feynman diagrams to be easily
generated within LaTeX with minimal user instructions and without the need of
external programs. It builds upon the Ti*k*Z package and leverages the graph
placement algorithms from Ti*k*Z in order to automate the placement of many
vertices. Ti*k*Z-Feynman still allows fine-tuned placement of vertices so that
even complex diagrams can still be generated with ease.

Ti*k*Z-Feynman is made available through the Comprehensive TeX Archive Network
(CTAN) and comes with some thorough
documentation
containing a tutorial and many examples. I have also submitted the
documentation for `v1.0.0` on the arXiv. If you use Ti*k*Z-Feynman,
please cite:

Joshua Ellis. ‘TikZ-Feynman: Feynman diagrams with TikZ’. arXiv: 1601.05437 [hep-ph]

Ti*k*Z-Feynman is open source and contribution are welcome. If you have any
suggestions, feature requests, or have found any bugs, feel free to create a new
issue or pull request on Github.

Below are a few example to demonstrate how easy diagram can be, and how extensible it can be. Many more are given in the documentation:

1 2 3 4 5 | ```
\feynmandiagram [horizontal=a to b] {
i1 -- [fermion] a -- [fermion] i2,
a -- [photon] b,
f1 -- [fermion] b -- [fermion] f2,
};
``` |

1 2 3 4 5 6 | ```
\feynmandiagram [large, vertical=e to f] {
a -- [fermion] b -- [photon, momentum=\(k\)] c -- [fermion] d,
b -- [fermion, momentum'=\(p_{1}\)] e -- [fermion, momentum'=\(p_{2}\)] c,
e -- [gluon] f,
h -- [fermion] f -- [fermion] i;
};
``` |

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 | ```
\begin{tikzpicture}
\begin{feynman}
\vertex (a1) {\(\overline b\)};
\vertex[right=1cm of a1] (a2);
\vertex[right=1cm of a2] (a3);
\vertex[right=1cm of a3] (a4) {\(b\)};
\vertex[right=1cm of a4] (a5);
\vertex[right=2cm of a5] (a6) {\(u\)};
\vertex[below=2em of a1] (b1) {\(d\)};
\vertex[right=1cm of b1] (b2);
\vertex[right=1cm of b2] (b3);
\vertex[right=1cm of b3] (b4) {\(\overline d\)};
\vertex[below=2em of a6] (b5) {\(\overline d\)};
\vertex[above=of a6] (c1) {\(\overline u\)};
\vertex[above=2em of c1] (c3) {\(d\)};
\vertex at ($(c1)!0.5!(c3) - (1cm, 0)$) (c2);
\diagram* {
{[edges=fermion]
(b1) -- (b2) -- (a2) -- (a1),
(b5) -- (b4) -- (b3) -- (a3) -- (a4) -- (a5) -- (a6),
},
(a2) -- [boson, edge label=\(W\)] (a3),
(b2) -- [boson, edge label'=\(W\)] (b3),
(c1) -- [fermion, out=180, in=-45] (c2) -- [fermion, out=45, in=180] (c3),
(a5) -- [boson, bend left, edge label=\(W^{-}\)] (c2),
};
\draw [decoration={brace}, decorate] (b1.south west) -- (a1.north west)
node [pos=0.5, left] {\(B^{0}\)};
\draw [decoration={brace}, decorate] (c3.north east) -- (c1.south east)
node [pos=0.5, right] {\(\pi^{-}\)};
\draw [decoration={brace}, decorate] (a6.north east) -- (b5.south east)
node [pos=0.5, right] {\(\pi^{+}\)};
\end{feynman}
\end{tikzpicture}
``` |