FEAT: check CP transformation in Julia (#222)

* updated the Euler-angles notebook
* add flip-all test
Co-authored-by: Remco de Boer <[email protected]>

Author: mmikhasenko

data/observable-references.yaml

@@ -26,3 +26,15 @@ Default amplitude model:
     D(1232): 28.60 ± 0.29 ± 0.76 ± 0.16
     D(1600): 4.5 ± 0.3 ± 1.5 ± 0.1
     D(1700): 3.90 ± 0.20 ± 0.94 ± 0.07
+Point cross-check:
+  variables:
+    m2pk: 3.64862611
+    m2kpi: 0.79807035
+    pk_theta_r: 1.06382395
+    pk_theta_p: -1.33775751
+    ppi_theta_r: -0.487513
+    ppi_theta_p: 1.11390452
+    kpi_theta_k: 1.82134117
+    p4p: [0.0, 0.0, 0.68416827, 1.16122377]
+    p4pi: [-0.28022697, 0.0, -0.1556354, 0.34961317]
+    p4k: [0.28022697, 0.0, -0.52853287, 0.77562306]