The Froissart–Stora equation describes the change in polarization which a high energy charged particle beam in a storage ring will undergo as it passes through a resonance in the spin tune.
[1] [2] It is named after the French physicists Marcel Froissart and Raymond Stora.
The Froissart–Stora equation has a direct analogy in condensed matter physics in the Landau–Zener effect.
In this case, there are additional polarization effects resulting from the synchrotron radiation.
In particular, the Sokolov–Ternov effect describes the polarization due to spin flip radiation.