Implement extra rotation for spin alignment of different sub-systems

[redeboer]

When dealing with different Subsystems in the same amplitude description, an extra rotation has to be introduced in order to align one system to another. Otherwise the phi angular distributions can be incorrect.

Different Subsystems means that intermediate states appear in different groups of final state particles.

Alignment methods

• Implement Dalitz-Plot Decomposition for Three-Body Decays #277
  Mikhashenko et al., “Dalitz-Plot Decomposition for Three-Body Decays”, 2020, 10.1103/PhysRevD.101.034033
• Wang et al., “A Novel Method to Test Particle Ordering and Final State Alignment in Helicity Formalism”, 2020, arXiv: 2012.03699
• feat!: implement spin alignment with DOI:10.1155/2020/6674595 #245
  Marangotto, “Helicity Amplitudes for Generic Multi-Body Particle Decays Featuring Multiple Decay Chains”, 2020, 10.1155/2020/6674595

Related literature

• Chilikin et al., “Experimental Constraints on the Spin and Parity of the Z(4430)+”, 2013, 10.1103/PhysRevD.88.074026. See Appendix A.
• Kutschke, “An Angular Distribution Cookbook”, 1996 [here]
• Richman, “An Experimenter’s Guide to the Helicity Formalism”, 1984 [here]