The analyzing power [math][/math]
The differential cross section for Compton scattering is given by the Klein-Nishina formula:
[math]\frac{d\sigma}{d\Omega} = \frac{1}{2} r_e^2 (P(E_\gamma,\theta) - P(E_\gamma,\theta)^2 \sin^2(\theta) + P(E_\gamma,\theta)^3)[/math]