# Gluon loop diagrams

I am trying to draw a gluon loop with two-three and four external gluon legs attached to the gluon loop, but as you may see from the attached file these diagrams are not nice enough, could anybody help me to draw them in a nice and symmetric way please? here comes what I have tried:

\documentclass{article}
\usepackage{feynmp}
%\usepackage{feynmf}
\DeclareGraphicsRule{*}{mps}{*}{}
\begin{document}
\begin{figure}[h]
\centering
\begin{eqnarray}
\non
\begin{fmffile}{gluoncasediagrams}
\newenvironment{8p}{
\begin{fmfgraph}(60,40)}
{\end{fmfgraph}}
\parbox{20mm}{
\begin{8p}
\fmfleft{i1,i2} \fmfright{o1,o2}
\fmf{gluon,fore=blue}{i1,v3}
% \fmflabel{$p_3,a_3,\mu_3$}{i1}
\fmf{gluon,fore=black}{i2,v4}
%\fmflabel{$p_4,a_4,\mu_4$}{i2}
\fmf{gluon,fore=red}{v2,o1}
%\fmflabel{$p_2,a_2,\mu_2$}{o1}
\fmf{gluon,fore=green}{v1,o2}
%\fmflabel{$p_1, a_1,\mu_1$}{o2}
\fmf{gluon,tension=0.1}{v1,v2}
\fmf{gluon,tension=0.3}{v2,v3}
\fmf{gluon,tension=0.3}{v3,v4}
\fmf{gluon,tension=0.3}{v4,v1}
\end{8p}}
\parbox{20mm}{
\begin{8p}
\fmfleft{i1,i2} \fmfright{o1,o2}
\fmf{gluon,fore=red}{i1,v1}
%\fmflabel{$p_2,a_2$}{i1}
\fmf{gluon,fore=blue}{i2,v2}
%\fmflabel{$p_3,a_3$}{i2}
\fmf{gluon,tension=4,fore=green}{v3,o1}
%\fmflabel{$p_1,a_1$}{o1}
\fmf{gluon,tension=4,fore=black}{v3,o2}
%\fmflabel{$p_4,a_4$}{o2}
\fmf{gluon,tension=0.1}{v2,v1}
\fmf{gluon,tension=0.3}{v1,v3}
\fmf{gluon,tension=0.3}{v3,v2}
\end{8p}}
\parbox{20mm}{
\begin{8p}
\fmfleft{i1,i2} \fmfright{o1,o2}
\fmf{gluon,fore=red}{i1,v1}
% \fmflabel{$p_2,a_2$}{i1}
\fmf{gluon,fore=blue}{i2,v1}
%\fmflabel{$p_3,a_3$}{i2}
\fmf{gluon,fore=green}{v2,o1}
%\fmflabel{$p_1,a_1$}{o1}
\fmf{gluon,fore=black}{v2,o2}
%\fmflabel{$p_4,a_4$}{o2}
\fmf{gluon,left,tension=.3}{v1,v2,v1}
\end{8p}}
\parbox{20mm}{
\begin{8p}
\fmfleft{i1,i2} \fmfright{o1,o2}
\fmf{gluon,fore=red}{i1,v2}
% \fmflabel{$p_2,a_2$}{i1}
\fmf{gluon,fore=blue}{i2,v1}
%\fmflabel{$p_3,a_3$}{i2}
\fmf{gluon,fore=green}{v2,o1}
%\fmflabel{$p_1,a_1$}{o1}
\fmf{gluon,fore=black}{v2,o2}
%\fmflabel{$p_4,a_4$}{o2}
\fmf{gluon,left,tension=.3}{v1,v2,v1}
\end{8p}}
\end{fmffile}
\end{eqnarray}
\end{figure}
\end{document}


-
Welcome to TeX SE. Note that you can format code by indenting it by 4 spaces or highlighting and using the {} button in the editing bar. – cfr Jun 30 '14 at 2:39
What exactly do you mean by "nice and symmetric"? I assume you don't want any of the gluon paths to intersect in their loops (and they look pretty symmetric to me, unless you'r taking about which way the gluon paths curl). I don't use feynmf, but have you tried the TikZ package with the path decoration coil (on page 588 of the manual)? – jlv Jun 30 '14 at 6:04
I would like to have a nice loop where the external gluons attached to it in a nicer way not like what I have done here. As you said I do not want the gluon paths to intersect in their loop like these! and do you know how can I change the angle of the external gluons, my last diagram is really ugly!thanks – Naser Jul 1 '14 at 6:11