# Feynman diagram: sides switched

In my t-channel Feynman diagram (with tikz-Feynman), the lower two particles of the t-channel are switched. It appears that for s-channel, the right hand side particles are switched too.

Code for t-channel:

\documentclass[a4paper]{article}
\usepackage{physics}
\usepackage{graphicx}
\usepackage[compat=1.1.0]{tikz-feynman}

\begin{document}

t-channel
$\feynmandiagram [large, vertical=a to b] { i1 [particle=$$\nu$$] -- [fermion, momentum=$$q$$] a -- [boson, momentum=$$k$$] f1 [particle=$$W^+$$], a -- [fermion, momentum=$$p$$] b, i2 [particle=$$\bar\nu$$] -- [anti fermion, momentum=$$q'$$] b, b -- [boson, momentum=$$k'$$] f2 [particle=$$W^-$$], };$

\end{document}


Expected output:

Got:

How can this be fixed?

## 1 Answer

You just need to switch the order of the lower two particles.

$\feynmandiagram [large, vertical=a to b] { i1 [particle=$$\nu$$] -- [fermion, momentum=$$q$$] a -- [boson, momentum=$$k$$] f1 [particle=$$W^+$$], a -- [fermion, momentum=$$p$$] b, b -- [boson, momentum=$$k'$$] f2 [particle=$$W^-$$], i2 [particle=$$\bar\nu$$] -- [anti fermion, momentum=$$q'$$] b, };$