As a step towards https://github.com/ComPWA/qrules/issues/219 and https://github.com/ComPWA/qrules/issues/20 (and an alternative to #266), it would be a good exercise to generate all allowed $J^{PC}$ numbers (spin, parity, $C$ parity) in a three-body decay using the CSPSolver directly (or if needed, using python-constraints directly). It's essentially reproducing the steps from the STM for a limited number of quantum numbers, without using a particle database.
### Tasks
An example from the visualization tutorial, $\psi^\prime \to \gamma \eta \eta$, i.e. $1^{--} \to 1^{--}\,0^{+-}\,0^{+-}$:
As a step towards https://github.com/ComPWA/qrules/issues/219 and https://github.com/ComPWA/qrules/issues/20 (and an alternative to #266), it would be a good exercise to generate all allowed $J^{PC}$ numbers (spin, parity, $C$ parity) in a three-body decay using the
CSPSolverdirectly (or if needed, usingpython-constraintsdirectly). It's essentially reproducing the steps from the STM for a limited number of quantum numbers, without using a particle database.An example from the visualization tutorial, $\psi^\prime \to \gamma \eta \eta$, i.e. $1^{--} \to 1^{--}\,0^{+-}\,0^{+-}$:
Particle transitions
