3

I am currently doing some work on the renormalization of the scalar phi^4 theory and i need to draw a feynman diagram of a first order loop correction. I have tried to follow the example on the manual but i keep getting my exiting lines crossing over the loop, and i would like to have them cross over outside the loop. My code looks like:

\begin{fmffile}{u_channel}
\begin{fmfgraph}(40,25)
\fmfleft{i1,i2}
\fmfright{o1,o2}
\fmf{plain}{i1,v1}
\fmf{phantom}{v1,o1}
\fmf{plain}{i2,v2}
\fmf{phantom}{v2,o2}
\fmf{dashes,left, tension=0.2}{v1,v2}
\fmf{dashes,right, tension=0.2}{v1,v2}
\fmf{plain, tension=0.2}{v1,o2}
\fmf{plain, tension=0.2}{v2,o1}
\end{fmfgraph}
\end{fmffile}

and my diagram ends up looking like this:

enter image description here

Any help would be much appreciated! Much love

Christhepanicker
  • 31

1 Answers1

1

Try to replace your last two crossing lines by

\fmf{plain,tension=0.2,right=0.5}{v1,o2}
\fmf{plain,tension=0.2,left=0.5,rubout}{v2,o1}
Werner
  • 603,163
user118270
  • 11