https://github.com/compwa/gluex-amplitude
https://github.com/compwa/gluex-amplitude
Last synced: about 1 year ago
JSON representation
- Host: GitHub
- URL: https://github.com/compwa/gluex-amplitude
- Owner: ComPWA
- License: bsd-3-clause
- Created: 2023-07-31T19:00:13.000Z (almost 3 years ago)
- Default Branch: main
- Last Pushed: 2025-04-07T21:14:21.000Z (about 1 year ago)
- Last Synced: 2025-04-07T22:25:40.234Z (about 1 year ago)
- Language: C++
- Homepage: https://compwa.github.io/gluex-amplitude
- Size: 205 KB
- Stars: 7
- Watchers: 8
- Forks: 1
- Open Issues: 6
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Comparison repository for GlueX amplitude models
[](https://github.com/astral-sh/ruff)
[](https://github.com/astral-sh/uv)
[](https://github.com/prettier/prettier)
This repository was created during PWA working group meetings for GlueX at Jefferson Lab, July 31st to August 4th, 2023. Live notes for these discussions can be found [here](https://hackmd.io/@QHYjhejHTIWXL2MltV3WNQ/r17prtBo3) on HackMD. Each meeting was organised like a 'hackathon' and the results of these programming sessions can be found on [compwa.github.io/gluex-amplitude](https://compwa.github.io/gluex-amplitude).
The main target for the week was to implement a simple intensity function for two-pseudoscalar system with photo-production:
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.
The details for this model have been worked out in [10.1103/PhysRevD.100.054017](https://doi.org/10.1103/PhysRevD.100.054017) (2019).
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 Project](https://compwa.github.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.
## Installation
### C++ implementation
This repository comes with [AmpTools](https://github.com/mashephe/AmpTools) as a submodule. If you clone this repository as:
```shell
git clone https://github.com/compwa/gluex-amplitude --recurse-submodules
```
you should get AmpTools as well. Navigate to [`extern/AmpTools`](./extern/AmpTools) for further build instructions. Additionally, you need to have ROOT installed. Official installation instructions can be found [here](https://root.cern/install), but alternatively, you can install ROOT in your conda environment (see [Python implementation](#python-implementation)) as follows:
```shell
conda activate gluex-amplitude
conda install root -c conda-forge
```
The benefit of AmpTools as a sub-module and installing ROOT into the conda environment is that you have out-of-the-box [language navigation in VSCode](https://code.visualstudio.com/docs/cpp/cpp-ide#_navigate-source-code).
To build all source code, you first need to compile AmpTools. Either do this by cloning AmpTools and following the instructions, or with:
```shell
cd extern/AmpTools
make
```
You can then compile the code for this repository by navigating back to the root directory (`cd ../../`) and running:
```
make
```
### Python implementation
Install Conda (recommended: [Miniconda](https://docs.conda.io/en/latest/miniconda.html#linux-installers)), then just create a Conda environment from [`environment.yml`](./environment.yml):
```shell
conda env create
conda activate gluex-amplitude
pre-commit install --install-hooks # optional
```
The Python implementation mainly consists of Jupyter notebooks located under the [`docs`](./docs) folder. It's best to view, run, and edit them with VSCode or with
```shell
jupyter lab
```
You can also run all notebooks and render them as static HTML pages with [Jupyter Book](https://jupyterbook.org) as follows:
```shell
jb build docs/ -W
```
Open `docs/_build/html/index.html` to view the resulting HTML pages. In VSCode, you can view the output HTML files by searching for "Live Preview: Start Server" through the [command pallette](https://code.visualstudio.com/api/ux-guidelines/command-palette) (`Ctrl+Shift+P`).