DOC: add Feynman diagram for vector meson decay

.gitignore

@@ -20,7 +20,11 @@ lib/
 version.py
 
 # Temporary files
+*.aux
+*.dvi
+*.log
 *.pyc
+*.synctex*
 *condaenv.*
 .coverage
 .coverage.*

.pre-commit-config.yaml

@@ -18,6 +18,10 @@ repos:
       - id: check-vcs-permalinks
       - id: check-yaml
       - id: end-of-file-fixer
+        exclude: >
+          (?x)^(
+            .*\.svg
+          )$
       - id: mixed-line-ending
       - id: trailing-whitespace
 
@@ -40,6 +44,13 @@ repos:
     hooks:
       - id: isort
 
+  - repo: https://github.com/cmhughes/latexindent.pl
+    rev: V3.22.2
+    hooks:
+      - id: latexindent
+        args:
+          - "-y=defaultIndent: '  '"
+
   - repo: https://github.com/nbQA-dev/nbQA
     rev: 1.7.0
     hooks:

.vscode/settings.json

@@ -28,5 +28,43 @@
     ".github/workflows/amptools.yml",
     ".github/workflows/docs.yml"
   ],
+  "latex-workshop.latex.autoBuild.run": "onSave",
+  "latex-workshop.latex.autoClean.run": "onSucceeded",
+  "latex-workshop.latex.clean.fileTypes": [
+    "%DOCFILE%.aux",
+    "%DOCFILE%.dvi",
+    "%DOCFILE%.log",
+    "%DOCFILE%.synctex",
+    "%DOCFILE%.synctex.gz"
+  ],
+  "latex-workshop.latex.clean.method": "glob",
+  "latex-workshop.latex.recipes": [
+    {
+      "name": "feynman",
+      "tools": ["pdf", "dvi", "svg"]
+    }
+  ],
+  "latex-workshop.latex.tools": [
+    {
+      "args": [
+        "-synctex=1",
+        "-interaction=nonstopmode",
+        "-file-line-error",
+        "%DOC%"
+      ],
+      "command": "lualatex",
+      "name": "pdf"
+    },
+    {
+      "args": ["--output-format=dvi", "%DOC%"],
+      "command": "lualatex",
+      "name": "dvi"
+    },
+    {
+      "args": ["--no-fonts", "%DOC%"],
+      "command": "dvisvgm",
+      "name": "svg"
+    }
+  ],
   "livePreview.defaultPreviewPath": "docs/_build/html"
 }

README.md

@@ -4,14 +4,16 @@ This repository was created during PWA working group meetings for GlueX at Jeffe
 
 The main target for the week was to implement a simple intensity function for two-pseudoscalar system with photo-production:
 
-![](docs/fig/eq-gluex-two-pseusoscalar.svg)
+![](docs/fig/eq-gluex-two-pseudoscalar.svg)
 
 where $Z_{l}^{m}(\Omega,\Phi)=Y_{l}^{m}(\Omega)e^{-i\Phi}$ is a phase-rotated spherical harmonic, $\Omega$ is the solid angle, $\Phi$ is the angle between the production and polarization planes, $P_{\gamma}$ is the polarization magnitude, $[l]$ are the partial wave amplitudes, $m$ is the associated m-projection, $k$ refers to a spin flip ($k=1$) or non-flip ($k=0$) at the nucleon vertex, and $\kappa$ is an overall phase space factor.
 
 ![](docs/fig/feynman-gluex-two-pseudoscalar.svg)
 
 The amplitude model is implemented in [AmpTools](https://github.com/mashephe/AmpTools) and symbolically in Python using [SymPy](https://docs.sympy.org) with additional tools from [`amptools`](https://ampform.rtfd.io) ([ComPWA](https://compwa-org.rtfd.io)). Dynamics are not yet included (model-indepedent by binning over energy). So we are just comparing linar combinations of spherical harmonics, but the comparison can be extended by investigating final states with a vector meson and/or parametrizing dynamic lineshapes.
 
+![](docs/fig/feynman-gluex-vector-meson.svg)
+
 ## Installation
 
 ### C++ implementation

docs/fig/eq-gluex-two-pseudoscalar.tex

@@ -0,0 +1,13 @@
+\documentclass{standalone}
+\usepackage{amsmath}
+
+\begin{document}
+\begin{math}
+  I(\Omega,\Phi) = 2\kappa\sum_{k}\Bigg(
+  (1-P_{\gamma})\left|\sum_{l,m}[l]_{m;k}^{(-)}\Re[Z_{l}^{m}(\Omega,\Phi)]\right|^2
+  +(1-P_{\gamma})\left|\sum_{l,m}[l]_{m;k}^{(+)}\Im[Z_{l}^{m}(\Omega,\Phi)]\right|^2
+  +(1+P_{\gamma})\left|\sum_{l,m}[l]_{m;k}^{(+)}\Re[Z_{l}^{m}(\Omega,\Phi)]\right|^2
+  +(1+P_{\gamma})\left|\sum_{l,m}[l]_{m;k}^{(-)}\Im[Z_{l}^{m}(\Omega,\Phi)]\right|^2
+  \Bigg)
+\end{math}
+\end{document}

docs/fig/feynman-gluex-two-pseudoscalar.tex

@@ -1,11 +1,10 @@
-\documentclass[a5paper]{article}
+\documentclass{standalone}
 \usepackage[compat=1.1.0]{tikz-feynman}
-\usepackage{nopageno}
 
 \begin{document}
 \Large
 \begin{tikzpicture}
-    \begin{feynman}
+  \begin{feynman}
     \vertex (a);
     \vertex [below=of a] (b);
     \vertex [right=of a] (c);
@@ -15,12 +14,11 @@
     \vertex [above right=of c] (f2) {\(\eta\)};
     \vertex [below right=of c] (f3) {\(\pi^0\)};
     \diagram* {
-        (i1) -- (a) --[scalar] (b) -- (i2),
-        (b) -- (f1),
-        (a) -- [blue, edge label=\(X\)](c),
-        (f2) -- (c) -- (f3),
+    (i1) -- [photon] (a) --[scalar] (b) -- (i2),
+    (b) -- (f1),
+    (a) -- [blue, edge label=\(X\)](c),
+    (f2) -- (c) -- (f3),
     };
-    \end{feynman}
+  \end{feynman}
 \end{tikzpicture}
-
 \end{document}

docs/fig/feynman-gluex-vector-meson.tex

@@ -0,0 +1,35 @@
+\documentclass{standalone}
+\usepackage[compat=1.1.0]{tikz-feynman}
+
+\begin{document}
+\Large
+\begin{tikzpicture}
+  \begin{feynman}
+    \vertex (a);
+    \vertex [below=of a] (b);
+    \vertex [right=of a] (c);
+    \vertex [above right=of c] (d);
+    \vertex [below right=of b] (e);
+    \vertex [below right=of e] (f1) {\(p\)};
+    \vertex [right=of e] (f2) {\(\pi^+\)};
+    \vertex [below right=of c] (f3) {\(\pi^-\)};
+    \vertex [above right=of d] (f4) {\(\pi^+\)};
+    \vertex [right=of d] (f5) {\(\pi^0\)};
+    \vertex [below right=of d] (f6) {\(\pi^-\)};
+    \vertex [above left=of a] (i1) {\(\gamma\)};
+    \vertex [below left=of b] (i2) {\(p\)};
+    \diagram* {
+    (i1) -- [photon] (a) --[scalar] (b) -- (i2),
+    (b) -- [edge label=\(\Delta^{++}\)] (e),
+    (a) -- [blue, edge label=\(X\)](c),
+    (c) -- [edge label=\(\omega\)] (d),
+    (e) -- (f1),
+    (e) -- (f2),
+    (c) -- (f3),
+    (d) -- (f4),
+    (d) -- (f5),
+    (d) -- (f6),
+    };
+  \end{feynman}
+\end{tikzpicture}
+\end{document}

docs/index.md

@@ -28,6 +28,9 @@ I(\Omega,\Phi) = 2\kappa\sum_{k}\left(
 :end-line: 13
 ```
 
+:::{figure} fig/feynman-gluex-vector-meson.svg
+:::
+
 See [the repository](https://github.com/compwa/gluex-amplitude) for installation instructions.
 
 ## Table of contents