Some leading-order diagrams of basic QCD processes, inspired by Table 7.1 of Griffith’s Introduction to Elementary Particles (2008).
- Electron-muon scattering
- Electron-electron scattering
- Electron-positron scattering
- Compton scattering
- Inelastic scattering
Electron-muon scattering
\documentclass[11pt,border=4pt]{standalone} \usepackage{feynmp-auto} \begin{document} \begin{fmffile}{feyngraph} \fmfframe(-2,12)(0,14){ % padding (L,T)(R,B) \begin{fmfgraph*}(100,60) % dimensions (WH) % external vertices \fmfleft{i2,i1} \fmfright{o2,o1} % main \fmf{fermion}{i1,v1,o1} \fmf{boson,tension=0.7,label.side=right,label=$\gamma$}{v1,v2} % t-channel \fmf{fermion}{i2,v2,o2} % labels \fmflabel{e$^-$}{i1} \fmflabel{$\mu^-$}{i2} \fmflabel{e$^-$}{o1} \fmflabel{$\mu^-$}{o2} \end{fmfgraph*} } % close \fmfframe \end{fmffile} \end{document}
Electron-electron scattering
Electron-electron scattering, also known as Møller scattering. The t-channel:
\documentclass[11pt,border=4pt]{standalone} \usepackage{feynmp-auto} \begin{document} \begin{fmffile}{feyngraph} \fmfframe(-2,12)(0,14){ % padding (L,T)(R,B) \begin{fmfgraph*}(100,60) % dimensions (WH) % external vertices \fmfleft{i2,i1} \fmfright{o2,o1} % main \fmf{fermion}{i1,v1,o1} \fmf{boson,tension=0.7,label.side=right,label=$\gamma$}{v1,v2} % t-channel \fmf{fermion}{i2,v2,o2} % labels \fmflabel{e$^-$}{i1} \fmflabel{e$^-$}{i2} \fmflabel{e$^-$}{o1} \fmflabel{e$^-$}{o2} \end{fmfgraph*} } % close \fmfframe \end{fmffile} \end{document}
The u-channel, using the style option “rubout” to create a white border around the crossing line:
\documentclass[11pt,border=4pt]{standalone} \usepackage{feynmp-auto} \begin{document} \begin{fmffile}{feyngraph} \fmfframe(-2,12)(0,14){ % padding (L,T)(R,B) \begin{fmfgraph*}(100,60) % dimensions (WH) % external vertices \fmfleft{i2,i1} \fmfright{o2,o1} % main \fmf{phantom}{i1,v1,o1} \fmf{boson,tension=0.7,label.side=right,label=$\gamma$}{v1,v2} % t-channel \fmf{phantom}{i2,v2,o2} \fmffreeze % main - outgoing lines \fmf{fermion,rubout}{i1,v1,o2} \fmf{fermion}{i2,v2,o1} % labels \fmflabel{e$^-$}{i1} \fmflabel{e$^-$}{i2} \fmflabel{e$^-$}{o1} \fmflabel{e$^-$}{o2} \end{fmfgraph*} } % close \fmfframe \end{fmffile} \end{document}
Electron-positron scattering
Electron-positron scattering, also known as Bhabba scattering. The t-channel:
\documentclass[11pt,border=4pt]{standalone} \usepackage{feynmp-auto} \begin{document} \begin{fmffile}{feyngraph} \fmfframe(-2,12)(0,14){ % padding (L,T)(R,B) \begin{fmfgraph*}(100,60) % dimensions (WH) % external vertices \fmfleft{i2,i1} \fmfright{o2,o1} % main \fmf{fermion}{i1,v1,o1} \fmf{boson,tension=0.7,label.side=right,label=$\gamma$}{v1,v2} % t-channel \fmf{fermion}{o2,v2,i2} % labels \fmflabel{e$^-$}{i1} \fmflabel{e$^+$}{i2} \fmflabel{e$^-$}{o1} \fmflabel{e$^+$}{o2} \end{fmfgraph*} } % close \fmfframe \end{fmffile} \end{document}
The u-channel:
\documentclass[11pt,border=4pt]{standalone} \usepackage{feynmp-auto} \begin{document} \begin{fmffile}{feyngraph} \fmfframe(-2,12)(0,14){ % padding (L,T)(R,B) \begin{fmfgraph*}(100,60) % dimensions (WH) % external vertices \fmfleft{i2,i1} \fmfright{o2,o1} % main \fmf{fermion}{i1,v1,i2} \fmf{boson,label.side=left,label=$\gamma$}{v1,v2} % s-channel \fmf{fermion}{o2,v2,o1} % labels \fmflabel{e$^-$}{i1} \fmflabel{e$^+$}{i2} \fmflabel{e$^-$}{o1} \fmflabel{e$^+$}{o2} \end{fmfgraph*} } % close \fmfframe \end{fmffile} \end{document}
Compton scattering
Compton scattering between an electron and photon. The t-channel:
\documentclass[11pt,border=4pt]{standalone} \usepackage{feynmp-auto} \begin{document} \begin{fmffile}{feyngraph} \fmfframe(-2,13)(0,14){ % padding (L,T)(R,B) \begin{fmfgraph*}(100,60) % dimensions (WH) % external vertices \fmfleft{i2,i1} \fmfright{o2,o1} % main \fmf{boson}{i1,v1} \fmf{fermion}{o1,v1} \fmf{fermion,tension=0.7}{v2,v1} % t-channel \fmf{boson}{o2,v2} \fmf{fermion}{v2,i2} % labels \fmflabel{$\gamma$}{i1} \fmflabel{e$^-$}{i2} \fmflabel{e$^-$}{o1} \fmflabel{$\gamma$}{o2} \end{fmfgraph*} } % close \fmfframe \end{fmffile} \end{document}
The s-channel:
\documentclass[11pt,border=4pt]{standalone} \usepackage{feynmp-auto} \begin{document} \begin{fmffile}{feyngraph} \fmfframe(-2,13)(0,14){ % padding (L,T)(R,B) \begin{fmfgraph*}(100,60) % dimensions (WH) % external vertices \fmfleft{i2,i1} \fmfright{o2,o1} % main \fmf{boson}{i1,v1} \fmf{fermion}{i2,v1} \fmf{fermion}{v1,v2} % s-channel \fmf{fermion}{v2,o2} \fmf{boson}{v2,o1} % labels \fmflabel{$\gamma$}{i1} \fmflabel{e$^-$}{i2} \fmflabel{$\gamma$}{o1} \fmflabel{e$^-$}{o2} \end{fmfgraph*} } % close \fmfframe \end{fmffile} \end{document}
Inelastic scattering
Pair annihilation in the t-channel:
\documentclass[11pt,border=4pt]{standalone} \usepackage{feynmp-auto} \begin{document} \begin{fmffile}{feyngraph} \fmfframe(-2,13)(0,14){ % padding (L,T)(R,B) \begin{fmfgraph*}(100,60) % dimensions (WH) % external vertices \fmfleft{i2,i1} \fmfright{o2,o1} % main \fmf{fermion}{i1,v1} \fmf{fermion}{v2,i2} \fmf{fermion,tension=0.7}{v1,v2} % t-channel \fmf{boson}{v1,o1} \fmf{boson}{v2,o2} % labels \fmflabel{e$^-$}{i1} \fmflabel{e$^+$}{i2} \fmflabel{$\gamma$}{o1} \fmflabel{$\gamma$}{o2} \end{fmfgraph*} } % close \fmfframe \end{fmffile} \end{document}
Pair annihilation in the u-channel:
\documentclass[11pt,border=4pt]{standalone} \usepackage{feynmp-auto} \begin{document} \begin{fmffile}{feyngraph} \fmfframe(-2,12)(0,14){ % padding (L,T)(R,B) \begin{fmfgraph*}(100,60) % dimensions (WH) % external vertices \fmfleft{i2,i1} \fmfright{o2,o1} % skeleton \fmf{phantom}{i1,v1,o1} \fmf{fermion,tension=0.7}{v1,v2} % t-channel \fmf{phantom}{i2,v2,o2} \fmffreeze % main incoming/outgoing lines \fmf{fermion}{i1,v1} \fmf{fermion}{v2,i2} \fmf{boson,rubout}{v1,o2} \fmf{boson}{v2,o1} % labels \fmflabel{e$^-$}{i1} \fmflabel{e$^+$}{i2} \fmflabel{$\gamma$}{o1} \fmflabel{$\gamma$}{o2} \end{fmfgraph*} } % close \fmfframe \end{fmffile} \end{document}
Pair creation in the t-channel:
\documentclass[11pt,border=4pt]{standalone} \usepackage{feynmp-auto} \begin{document} \begin{fmffile}{feyngraph} \fmfframe(-2,13)(0,14){ % padding (L,T)(R,B) \begin{fmfgraph*}(100,60) % dimensions (WH) % external vertices \fmfleft{i2,i1} \fmfright{o2,o1} % main \fmf{boson}{i1,v1} \fmf{boson}{v2,i2} \fmf{fermion,tension=0.7}{v2,v1} % t-channel \fmf{fermion}{v1,o1} \fmf{fermion}{o2,v2} % labels \fmflabel{$\gamma$}{i1} \fmflabel{$\gamma$}{i2} \fmflabel{e$^-$}{o1} %\fmflabel{e$^+$}{o2} \fmfv{l.d=4,l.a=-25,l=e$^+$}{o2} % more control \end{fmfgraph*} } % close \fmfframe \end{fmffile} \end{document}
Pair creation in the u-channel:
\documentclass[11pt,border=4pt]{standalone} \usepackage{feynmp-auto} \begin{document} \begin{fmffile}{feyngraph} \fmfframe(-2,12)(0,14){ % padding (L,T)(R,B) \begin{fmfgraph*}(100,60) % dimensions (WH) % external vertices \fmfleft{i2,i1} \fmfright{o2,o1} % skeleton \fmf{phantom}{i1,v1,o1} \fmf{fermion,tension=0.7}{v1,v2} % t-channel \fmf{phantom}{i2,v2,o2} \fmffreeze % main incoming/outgoing lines \fmf{boson}{i1,v1} \fmf{boson}{i2,v2} \fmf{fermion}{v2,o1} \fmf{fermion,rubout}{o2,v1} % labels \fmflabel{$\gamma$}{i1} \fmflabel{$\gamma$}{i2} \fmflabel{e$^-$}{o1} %\fmflabel{e$^+$}{o2} \fmfv{l.d=4,l.a=-25,l=e$^+$}{o2} % more control \end{fmfgraph*} } % close \fmfframe \end{fmffile} \end{document}
Full code
The LaTeX code below collects all the diagrams above into one big file that produces a multipage PDF. Please find download links below, or edit and compile here if you like:
% !TEX program = pdflatexmk % !TEX parameter = -shell-escape % Author: Izaak Neutelings (August 2024) % Description: Basic LO QED processes % Instructions: To compile via command line, run the following twice % pdflatex -shell-escape basic_QED.tex \documentclass[11pt,border=4pt,multi=page,crop]{standalone} \usepackage{feynmp-auto} % DEFINE fmfpicture ENVIRONMENT \usepackage{environ} % for \NewEnviron \DeclareGraphicsRule{*}{mps}{*}{} \NewEnviron{fmfpicture}[3]{% \begin{page} % to create standalone page \fmfframe(#1)(#2){ % padding (L,T)(R,B) \begin{fmffile}{feynmp-#3} % auxiliary files (use unique name!) \BODY % main code \end{fmffile} } \end{page} } \begin{document} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%% ELECTRON-MUON SCATTERING %%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % ELECTRON-MUON SCATTERING (Mott/Rutherford) - t-channel \begin{fmfpicture}{-2,12}{0,14}{em-em-tchan} % padding (LTRB) \begin{fmfgraph*}(100,60) % dimensions (WH) % external vertices \fmfleft{i2,i1} \fmfright{o2,o1} % main \fmf{fermion}{i1,v1,o1} \fmf{boson,tension=0.7,label.side=right,label=$\gamma$}{v1,v2} % t-channel \fmf{fermion}{i2,v2,o2} % labels \fmflabel{e$^-$}{i1} \fmflabel{$\mu^-$}{i2} \fmflabel{e$^-$}{o1} \fmflabel{$\mu^-$}{o2} \end{fmfgraph*} \end{fmfpicture} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%% ELECTRON-ELECTRON SCATTERING %%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % ELECTRON-ELECTRON SCATTERING (Moller) - t-channel \begin{fmfpicture}{-2,12}{0,14}{ee-ee-tchan} % padding (LTRB) \begin{fmfgraph*}(100,60) % dimensions (WH) % external vertices \fmfleft{i2,i1} \fmfright{o2,o1} % main \fmf{fermion}{i1,v1,o1} \fmf{boson,tension=0.7,label.side=right,label=$\gamma$}{v1,v2} % t-channel \fmf{fermion}{i2,v2,o2} % labels \fmflabel{e$^-$}{i1} \fmflabel{e$^-$}{i2} \fmflabel{e$^-$}{o1} \fmflabel{e$^-$}{o2} \end{fmfgraph*} \end{fmfpicture} % ELECTRON-ELECTRON SCATTERING (Moller) - u-channel \begin{fmfpicture}{-2,12}{0,14}{ee-ee-uchan} % padding (LTRB) \begin{fmfgraph*}(100,60) % dimensions (WH) % external vertices \fmfleft{i2,i1} \fmfright{o2,o1} % main \fmf{phantom}{i1,v1,o1} \fmf{boson,tension=0.7,label.side=right,label=$\gamma$}{v1,v2} % t-channel \fmf{phantom}{i2,v2,o2} \fmffreeze % main - outgoing lines \fmf{fermion,rubout}{i1,v1,o2} \fmf{fermion}{i2,v2,o1} % labels \fmflabel{e$^-$}{i1} \fmflabel{e$^-$}{i2} \fmflabel{e$^-$}{o1} \fmflabel{e$^-$}{o2} \end{fmfgraph*} \end{fmfpicture} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%% ELECTRON-POSITRON SCATTERING %%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % ELECTRON-POSITRON SCATTERING (Bhabba) - t-channel \begin{fmfpicture}{-2,12}{0,14}{ep-ep-tchan} % padding (LTRB) \begin{fmfgraph*}(100,60) % dimensions (WH) % external vertices \fmfleft{i2,i1} \fmfright{o2,o1} % main \fmf{fermion}{i1,v1,o1} \fmf{boson,tension=0.7,label.side=right,label=$\gamma$}{v1,v2} % t-channel \fmf{fermion}{o2,v2,i2} % labels \fmflabel{e$^-$}{i1} \fmflabel{e$^+$}{i2} \fmflabel{e$^-$}{o1} \fmflabel{e$^+$}{o2} \end{fmfgraph*} \end{fmfpicture} % ELECTRON-POSITRON SCATTERING - s-channel \begin{fmfpicture}{-2,12}{0,14}{ep-ep-schan} % padding (LTRB) \begin{fmfgraph*}(100,60) % dimensions (WH) % external vertices \fmfleft{i2,i1} \fmfright{o2,o1} % main \fmf{fermion}{i1,v1,i2} \fmf{boson,label.side=left,label=$\gamma$}{v1,v2} % s-channel \fmf{fermion}{o2,v2,o1} % labels \fmflabel{e$^-$}{i1} \fmflabel{e$^+$}{i2} \fmflabel{e$^-$}{o1} \fmflabel{e$^+$}{o2} \end{fmfgraph*} \end{fmfpicture} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%% COMPTON SCATTERING %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % COMPTON SCATTERING - t-channel \begin{fmfpicture}{-2,13}{0,14}{eg-eg-tchan} % padding (LTRB) \begin{fmfgraph*}(100,60) % dimensions (WH) % external vertices \fmfleft{i2,i1} \fmfright{o2,o1} % main \fmf{boson}{i1,v1} \fmf{fermion}{o1,v1} \fmf{fermion,tension=0.7}{v2,v1} % t-channel \fmf{boson}{o2,v2} \fmf{fermion}{v2,i2} % labels \fmflabel{$\gamma$}{i1} \fmflabel{e$^-$}{i2} \fmflabel{e$^-$}{o1} \fmflabel{$\gamma$}{o2} \end{fmfgraph*} \end{fmfpicture} % COMPTON SCATTERING - s-channel \begin{fmfpicture}{-2,13}{0,14}{eg-eg-schan} % padding (LTRB) \begin{fmfgraph*}(100,60) % dimensions (WH) % external vertices \fmfleft{i2,i1} \fmfright{o2,o1} % main \fmf{boson}{i1,v1} \fmf{fermion}{i2,v1} \fmf{fermion}{v1,v2} % s-channel \fmf{fermion}{v2,o2} \fmf{boson}{v2,o1} % labels \fmflabel{$\gamma$}{i1} \fmflabel{e$^-$}{i2} \fmflabel{$\gamma$}{o1} \fmflabel{e$^-$}{o2} \end{fmfgraph*} \end{fmfpicture} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%% INELASTIC SCATTERING %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % PAIR ANNIHILATION - t-channel \begin{fmfpicture}{-2,13}{0,14}{ep-gg-tchan} % padding (LTRB) \begin{fmfgraph*}(100,60) % dimensions (WH) % external vertices \fmfleft{i2,i1} \fmfright{o2,o1} % main \fmf{fermion}{i1,v1} \fmf{fermion}{v2,i2} \fmf{fermion,tension=0.7}{v1,v2} % t-channel \fmf{boson}{v1,o1} \fmf{boson}{v2,o2} % labels \fmflabel{e$^-$}{i1} \fmflabel{e$^+$}{i2} \fmflabel{$\gamma$}{o1} \fmflabel{$\gamma$}{o2} \end{fmfgraph*} \end{fmfpicture} % PAIR ANNIHILATION - u-channel \begin{fmfpicture}{-2,12}{0,14}{ep-gg-uchan} % padding (LTRB) \begin{fmfgraph*}(100,60) % dimensions (WH) % external vertices \fmfleft{i2,i1} \fmfright{o2,o1} % skeleton \fmf{phantom}{i1,v1,o1} \fmf{fermion,tension=0.7}{v1,v2} % t-channel \fmf{phantom}{i2,v2,o2} \fmffreeze % main incoming/outgoing lines \fmf{fermion}{i1,v1} \fmf{fermion}{v2,i2} \fmf{boson,rubout}{v1,o2} \fmf{boson}{v2,o1} % labels \fmflabel{e$^-$}{i1} \fmflabel{e$^+$}{i2} \fmflabel{$\gamma$}{o1} \fmflabel{$\gamma$}{o2} \end{fmfgraph*} \end{fmfpicture} % PAIR CREATION - t-channel \begin{fmfpicture}{-2,13}{0,14}{gg-ep-tchan} % padding (LTRB) \begin{fmfgraph*}(100,60) % dimensions (WH) % external vertices \fmfleft{i2,i1} \fmfright{o2,o1} % main \fmf{boson}{i1,v1} \fmf{boson}{v2,i2} \fmf{fermion,tension=0.7}{v2,v1} % t-channel \fmf{fermion}{v1,o1} \fmf{fermion}{o2,v2} % labels \fmflabel{$\gamma$}{i1} \fmflabel{$\gamma$}{i2} \fmflabel{e$^-$}{o1} %\fmflabel{e$^+$}{o2} \fmfv{l.d=4,l.a=-25,l=e$^+$}{o2} % more control \end{fmfgraph*} \end{fmfpicture} % PAIR CREATION - u-channel \begin{fmfpicture}{-2,12}{0,14}{gg-ep-uchan} % padding (LTRB) \begin{fmfgraph*}(100,60) % dimensions (WH) % external vertices \fmfleft{i2,i1} \fmfright{o2,o1} % skeleton \fmf{phantom}{i1,v1,o1} \fmf{fermion,tension=0.7}{v1,v2} % t-channel \fmf{phantom}{i2,v2,o2} \fmffreeze % main incoming/outgoing lines \fmf{boson}{i1,v1} \fmf{boson}{i2,v2} \fmf{fermion}{v2,o1} \fmf{fermion,rubout}{o2,v1} % labels \fmflabel{$\gamma$}{i1} \fmflabel{$\gamma$}{i2} \fmflabel{e$^-$}{o1} %\fmflabel{e$^+$}{o2} \fmfv{l.d=4,l.a=-25,l=e$^+$}{o2} % more control \end{fmfgraph*} \end{fmfpicture} \end{document}
Click to download: basic_QED.tex • basic_QED.pdf
Open in Overleaf: basic_QED.tex.